Java Program to Compute the Sum of Diagonals of a Matrix Last Updated : 21 May, 2025 Comments Improve Suggest changes Like Article Like Report For a given 2D square matrix of size N*N, our task is to find the sum of elements in the Principal and Secondary diagonals. For example, analyze the following 4 × 4 input matrix.m00 m01 m02 m03m10 m11 m12 m13m20 m21 m22 m23m30 m31 m32 m33Basic Input/Output:Input 1: 6 7 3 4 8 9 2 1 1 2 9 6 6 5 7 2Output 1: Principal Diagonal: 26 Secondary Diagonal: 14 Input 2: 2 2 2 1 1 1 3 3 3Output 2: Principal Diagonal: 6 Secondary Diagonal: 6Understanding Diagonals in a Square Matrix:The diagonal on which the row number and column number are the same (like elements in positions like (1,1), (2,2), (3,3), (4,4), and so on) is known as the principal diagonal or main diagonal of a square matrix.The diagonal in which the sum of the row number and column number is equal to one less than the size of the matrix is called the secondary diagonal. It runs from the top-right corner to the bottom-left corner of a square matrix.Naive Approach: Using Nested Loops to Identify DiagonalsWe are going to use nested loops to iterate over the elements in the matrix and going to check if it belongs to the principal or secondary diagonal based on the condition.Example: Below is the naive approach for finding the sum of diagonals of a matrix. Java // Java Program to Find the Sum of Diagonals of a Matrix // Importing input output classes import java.io.*; // Main Class public class Geeks { // To calculate Sum of Diagonals static void Sum_of_Diagonals1(int[][] matrix, int N) { // Declaring and initializing two variables to zero // initially for primary and secondary diagonal // count int Pd = 0, Sd = 0; // Two Nested for loops for iteration over a matrix // Outer loop for rows for (int k = 0; k < N; k++) { // Inner loop for columns for (int l = 0; l < N; l++) { // Condition for the principal // diagonal if (k == l) Pd += matrix[k][l]; // Condition for the secondary diagonal if ((k + l) == (N - 1)) Sd += matrix[k][l]; } } // Print and display the sum of primary diagonal System.out.println("Sum of Principal Diagonal:" + Pd); // Print and display the sum of secondary diagonal System.out.println("Sum of Secondary Diagonal:" + Sd); } // Main driver method static public void main(String[] args) { // Input integer array // Custom entries in an array int[][] b = { { 8, 2, 13, 4 }, { 9, 16, 17, 8 }, { 1, 22, 3, 14 }, { 15, 6, 17, 8 } }; // Passing the array as an argument to the // function defined above Sum_of_Diagonals1(b, 4); } } OutputSum of Principal Diagonal:35 Sum of Secondary Diagonal:58 Time complexity: O(N2)Auxiliary space: O(1)Let's now discuss the efficient approach in order to solve this problem.Optimized Approach: Access Diagonal Elements Directly by IndexThe idea to find the sum of values of principal diagonal is to iterate to N and use the value of matrix[row][row] for the summation of principal diagonal and to find the sum of values of secondary diagonal is to use the value of matrix[row][N - (row + 1)] for summation.Example: Below is the efficient approach for finding the sum of diagonals of a matrix. Java // Java Program to Find the Sum of Diagonals of a Matrix // Importing input output classes import java.io.*; // Main Class public class Geeks { // To calculate Sum of Diagonals static void Sum_of_Diagonals(int[][] matrix, int N) { // Declaring and initializing two variables to zero // initially for primary and secondary diagonal // count int Pd = 0, Sd = 0; for(int i=0; i<N; i++) { // Since for primary diagonal sum the value of // row and column are equal Pd += matrix[i][i]; // For secondary diagonal sum values of i'th index // and j'th index sum is equal to n-1 at each // stage of matrix Sd += matrix[i][N-(i+1)]; } // Print and display the sum of primary diagonal System.out.println("Sum of Principal Diagonal:" + Pd); // Print and display the sum of secondary diagonal System.out.println("Sum of Secondary Diagonal:" + Sd); } // Main driver method static public void main(String[] args) { // Input integer array // Custom entries in an array int[][] b = { { 8, 2, 13, 4 }, { 9, 16, 17, 8 }, { 1, 22, 3, 14 }, { 15, 6, 17, 8 } }; // Passing the array as an argument to the // function defined above Sum_of_Diagonals(b, 4); } } OutputSum of Principal Diagonal:35 Sum of Secondary Diagonal:58 Time complexity: O(N)Auxiliary space: O(1) Comment More infoAdvertise with us Next Article Java Program to Interchange Elements of First and Last in a Matrix Across Rows K Kanchan_Ray Follow Improve Article Tags : Java Java-Array-Programs Practice Tags : Java Similar Reads Java Programs - Java Programming Examples In this article, we will learn and prepare for Interviews using Java Programming Examples. From basic Java programs like the Fibonacci series, Prime numbers, Factorial numbers, and Palindrome numbers to advanced Java programs.Java is one of the most popular programming languages today because of its 8 min read Java Basic ProgramsHow to Read and Print an Integer Value in Java?The given task is to take an integer as input from the user and print that integer in Java. To read and print an integer value in Java, we can use the Scanner class to take input from the user. This class is present in the java.util package.Example input/output:Input: 357Output: 357Input: 10Output: 3 min read Ways to Read Input from Console in JavaIn Java, there are four different ways to read input from the user in the command line environment(console). 1. Using Buffered Reader ClassBuffered Reader Class is the classical method to take input, Introduced in JDK 1.0. This method is used by wrapping the System.in (standard input stream) in an I 5 min read Java Program to Multiply two Floating-Point NumbersThe float class is a wrapper class for the primitive type float which contains several methods to effectively deal with a float value like converting it to a string representation, and vice-versa. An object of the Float class can hold a single float value. The task is to multiply two Floating point 1 min read Java Program to Swap Two NumbersProblem Statement: Given two integers m and n. The goal is simply to swap their values in the memory block and write the java code demonstrating approaches.Illustration:Input : m=9, n=5Output : m=5, n=9 Input : m=15, n=5Output : m=5, n=15Here 'm' and 'n' are integer valueApproaches:There are 3 stand 6 min read Java Program to Add Two Binary StringsWhen two binary strings are added, then the sum returned is also a binary string. Example: Input : x = "10", y = "01" Output: "11"Input : x = "110", y = "011" Output: "1001" Explanation: 110 + 011 =1001Approach 1: Here, we need to start adding from the right side and when the sum returned is more th 3 min read Java Program to Add two Complex NumbersComplex numbers are numbers that consist of two parts — a real number and an imaginary number. Complex numbers are the building blocks of more intricate math, such as algebra. The standard format for complex numbers is a + bi, with the real number first and the imaginary number last. General form fo 3 min read Java Program to Check if a Given Integer is Odd or EvenA number that is divisible by 2 and generates a remainder of 0 is called an even number. All the numbers ending with 0, 2, 4, 6, and 8 are even numbers. On the other hand, number that is not divisible by 2 and generates a remainder of 1 is called an odd number. All the numbers ending with 1, 3, 5,7, 7 min read Java Program to Find the Largest of three NumbersProblem Statement: Given three numbers x, y, and z of which aim is to get the largest among these three numbers.Example: Input: x = 7, y = 20, z = 56Output: 56 // value stored in variable zFlowchart For Largest of 3 numbers:Algorithm to find the largest of three numbers:1. Start2. Read the three num 4 min read Java Program to Find LCM of Two NumbersLCM (i.e. Least Common Multiple) is the largest of the two stated numbers that can be divided by both the given numbers. In this article, we will write a program to find the LCM in Java Java Program to Find the LCM of Two NumbersThe easiest approach for finding the LCM is to Check the factors and th 2 min read Java Program to Find GCD or HCF of Two NumbersGCD (i.e. Greatest Common Divisor) or HCF (i.e. Highest Common Factor) is the largest number that can divide both the given numbers. Example: HCF of 10 and 20 is 10, and HCF of 9 and 21 is 3.Therefore, firstly find all the prime factors of both the stated numbers, then find the intersection of all t 2 min read Java Program to Display All Prime Numbers from 1 to NFor a given number N, the purpose is to find all the prime numbers from 1 to N.Examples: Input: N = 11Output: 2, 3, 5, 7, 11Input: N = 7Output: 2, 3, 5, 7 Approach 1:Firstly, consider the given number N as input.Then apply a for loop in order to iterate the numbers from 1 to N.At last, check if each 4 min read Java Program to Find if a Given Year is a Leap YearLeap Year contains 366 days, which comes once every four years. In this article, we will learn how to write the leap year program in Java. Facts about Leap YearEvery leap year corresponds to these facts : A century year is a year ending with 00. A century year is a leap year only if it is divisible 5 min read Java Program to Check Armstrong Number between Two IntegersA positive integer with digits p, q, r, s…, is known as an Armstrong number of order n if the following condition is fulfilled. pqrs... = pn + qn + rn + sn +....Example: 370 = 3*3*3 + 7*7*7 + 0 = 27 + 343 + 0 = 370Therefore, 370 is an Armstrong number. Examples: Input : 100 200 Output :153 Explanati 2 min read Java Program to Check If a Number is Neon Number or NotA neon number is a number where the sum of digits of the square of the number is equal to the number. The task is to check and print neon numbers in a range. Illustration: Case 1: Input : 9 Output : Given number 9 is Neon number Explanation : square of 9=9*9=81; sum of digit of square : 8+1=9(which 3 min read Java Program to Check Whether the Character is Vowel or ConsonantIn this article, we are going to learn how to check whether a character is a vowel or a consonant. So, the task is, for any given character, we need to check if it is a vowel or a consonant. As we know, vowels are ‘a’, ‘e’, ‘i’, ‘o’, ‘u’ and all the other characters (i.e. ‘b’, ‘c’, ‘d’, ‘f’ …..) are 4 min read Java Program for Factorial of a NumberThe factorial of a non-negative integer is multiplication of all integers smaller than or equal to n. In this article, we will learn how to write a program for the factorial of a number in Java.Formulae for Factorialn! = n * (n-1) * (n-2) * (n-3) * ........ * 1 Example:6! == 6*5*4*3*2*1 = 720. 5! == 3 min read Java Program to Find Sum of Fibonacci Series Numbers of First N Even IndexesFor a given positive integer N, the purpose is to find the value of F2 + F4 + F6 +………+ F2n till N number. Where Fi indicates the i'th Fibonacci number. The Fibonacci Series is the numbers in the below-given integer sequence. 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ……Examples: Input: n = 4 Output: 3 4 min read Java Program to Calculate Simple InterestSimple interest is a quick method of calculating the interest charge on a loan. Simple interest is determined by multiplying the daily interest rate by the principal by the number of days that elapse between payments. Simple interest formula is given by:Simple Interest = (P x T x R)/100 Where, P is 2 min read Java Program for compound interestCompound Interest formula: Formula to calculate compound interest annually is given by: Compound Interest = P(1 + R/100)t Where, P is principal amount R is the rate and T is the time span Example: Input : Principal (amount): 1200 Time: 2 Rate: 5.4 Output : Compound Interest = 1333.099243 Java Code J 1 min read Java Program to Find the Perimeter of a RectangleA Rectangle is a quadrilateral with four right angles (90°). In a rectangle, the opposite sides are equal. A rectangle with all four sides equal is called a Square. A rectangle can also be called as right angled parallelogram. Rectangle In the above rectangle, the sides A and C are equal and B and D 2 min read Java Pattern ProgramsJava Program to Print Right Triangle Star PatternIn this article, we will learn about printing Right Triangle Star Pattern. Examples: Input : n = 5 Output: * * * * * * * * * * * * * * * Right Triangle Star Pattern: Java import java.io.*; // Java code to demonstrate right star triangle public class GeeksForGeeks { // Function to demonstrate printin 5 min read Java Program to Print Left Triangle Star PatternIn this article, we will learn about printing Left Triangle Star Pattern. Examples: Input : n = 5 Output: * * * * * * * * * * * * * * * Left Triangle Star Pattern: Java import java.io.*; // java program for left triangle public class GFG { // Function to demonstrate printing pattern public static vo 5 min read Java Program to Print Pyramid Number PatternHere we are getting a step ahead in printing patterns as in generic we usually play with columnar printing in the specific row keep around where elements in a row are either added up throughout or getting reduced but as we move forward we do start playing with rows which hold for outer loop in our p 2 min read Java Program to Print Reverse Pyramid Star PatternApproach: 1. Get the number of input rows from the user using Scanner Class or BufferedReader Class object. 2. Now run two loops Outer loop to iterate through a number of rows as initialized or input is taken from reader class object in java. Now,Run an inner loop from 1 to 'i-1'Ru another inner loo 4 min read Java Program to Print Upper Star Triangle PatternThe upper star triangle pattern means the base has to be at the bottom and there will only be one star to be printed in the first row. Here is the issue that will arise is what way we traverse be it forward or backward we can't ignore the white spaces, so we are not able to print a star in the first 2 min read Java Program to Print Mirror Upper Star Triangle PatternThe pattern has two parts - both mirror reflections of each other. The base of the triangle has to be at the bottom of the imaginary mirror and the tip at the top. Illustration: Input: size = 7 Output: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 5 min read Java Program to Print Downward Triangle Star PatternDownward triangle star pattern means we want to print a triangle that is downward facing means base is upwards and by default, orientation is leftwards so the desired triangle to be printed should look like * * * * * * * * * * Example Java // Java Program to Print Lower Star Triangle Pattern // Main 2 min read Java Program to Print Mirror Lower Star Triangle PatternIn this article, we are going to learn how to print mirror lower star triangle patterns in Java. Illustration: Input: number = 7 Output: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Methods: We can print mirror lower star triangle pa 5 min read Java Program to Print Star Pascal’s TrianglePascal’s triangle is a triangular array of the binomial coefficients. Write a function that takes an integer value n as input and prints the first n lines of Pascal’s triangle. Following are the first 6 rows of Pascal’s Triangle.In this article, we will look into the process of printing Pascal's tri 4 min read Java Program to Print Diamond Shape Star PatternIn this article, we are going to learn how to print diamond shape star patterns in Java. Illustration: Input: number = 7 Output: * *** ***** ******* ********* *********** ************* *********** ********* ******* ***** *** * Methods: When it comes to pattern printing we do opt for standard ways of 6 min read Java Program to Print Square Star PatternHere, we will implement a Java program to print the square star pattern. We will print the square star pattern with diagonals and without diagonals. Example: ********************** * * * * * * * * * * * * ********************** Approach: Step 1: Input number of rows and columns. Step 2: For rows of 4 min read Java Program to Print Pyramid Star PatternThis article will guide you through the process of printing a Pyramid star pattern in Java. 1. Simple pyramid pattern Java import java.io.*; // Java code to demonstrate Pyramid star patterns public class GeeksForGeeks { // Function to demonstrate printing pattern public static void PyramidStar(int n 5 min read Java Program to Print Spiral Pattern of NumbersIn Java, printing a spiral number is a very common programming task, which helps us to understand loops and array manipulation in depth. In this article, we are going to print a spiral pattern of numbers for a given size n.What is a Spiral Pattern?A spiral pattern is a sequence of numbers arranged i 3 min read Java Conversion ProgramsJava Program to Convert Binary to OctalA Binary (base 2) number is given, and our task is to convert it into an Octal (base 8) number. There are different ways to convert binary to decimal, which we will discuss in this article.Example of Binary to Octal Conversion:Input : 100100Output: 44Input : 1100001Output : 141A Binary Number System 5 min read Java Program to Convert Octal to DecimalOctal numbers are numbers with 8 bases and use digits from 0-7. This system is a base 8 number system. The decimal numbers are the numbers with 10 as their base and use digits from 0-9 to represent the decimal number. They also require dots to represent decimal fractions.We have to convert a number 3 min read Java Program For Decimal to Octal ConversionGiven a decimal number N, convert N into an equivalent octal number, i.e., convert the number with base value 10 to base value 8. The decimal number system uses 10 digits from 0-9, and the octal number system uses 8 digits from 0-7 to represent any numeric value.Illustration: Basic input/output for 3 min read Java Program for Hexadecimal to Decimal ConversionGiven a Hexadecimal (base 16) number N, and our task is to convert the given Hexadecimal number to a Decimal (base 10). The hexadecimal number uses the alpha-numeric values 0-9 and A- F. And the decimal number uses the numeric values 0-9. Example: Input : 1ABOutput: 427Input : 1AOutput: 26Approach t 3 min read Java Program For Decimal to Hexadecimal ConversionGiven a decimal number N, convert N into an equivalent hexadecimal number i.e. convert the number with base value 10 to base value 16. The decimal number system uses 10 digits 0-9 and the Hexadecimal number system uses 0-9, A-F to represent any numeric value.Examples of Decimal to Hexadecimal Conver 3 min read Java Program for Decimal to Binary ConversionGiven a decimal number as input, we need to write a program to convert the given decimal number into an equivalent binary number.Examples: Input : 7Output : 111Input: 33Output: 100001Binary-to-decimal conversion is done to convert a number given in the binary system to its equivalent in the decimal 5 min read Java Program for Decimal to Binary ConversionGiven a decimal number as input, we need to write a program to convert the given decimal number into an equivalent binary number.Examples: Input : 7Output : 111Input: 33Output: 100001Binary-to-decimal conversion is done to convert a number given in the binary system to its equivalent in the decimal 5 min read Boolean toString() Method in JavaIn Java, the toString() method of the Boolean class is a built-in method to return the Boolean value in string format. The Boolean class is a part of java.lang package. This method is useful when we want the output in the string format in places like text fields, console output, or simple text forma 2 min read Convert String to Double in JavaIn this article, we will convert a String to a Double in Java. There are three methods for this conversion from String to Double, as mentioned below in the article.Methods for String-to-Double ConversionDifferent ways for converting a String to a Double are mentioned below:Using the parseDouble() me 3 min read Java Program to Convert Double to StringThe primary goal of double to String conversion in Java is to store big streams of numbers that are coming where even data types fail to store the stream of numbers. It is generically carried out when we want to display the bigger values. In this article, we will learn How to Convert double to Strin 3 min read Java Program to Convert String to LongTo convert a String to Long in Java, we can use built-in methods provided by the Long class. In this article, we will learn how to convert String to Long in Java with different methods. Example:In the below example, we use the most common method i.e. Long.parseLong() method to convert a string to a 3 min read Java Program to Convert Long to StringThe long to String conversion in Java generally comes in need when we have to display a long number in a GUI application because everything is displayed in string form. In this article, we will learn about Java Programs to convert long to String. Given a Long number, the task is to convert it into a 4 min read Java Program For Int to Char ConversionIn this article, we will check how to convert an Int to a Char in Java. In Java, char takes 2 bytes (16-bit UTF encoding ), while int takes 4 bytes (32-bit). So, if we want the integer to get converted to a character then we need to typecast because data residing in 4 bytes cannot get into a single 3 min read Java Program to Convert Char to IntGiven a char value, and our task is to convert it into an int value in Java. We can convert a Character to its equivalent Integer in different ways, which are covered in this article.Examples of Conversion from Char to Int:Input : ch = '3'Output : 3Input : ch = '9'Output : 9The char data type is a s 4 min read Java Classes and Object ProgramsClasses and Objects in JavaIn Java, classes and objects are basic concepts of Object Oriented Programming (OOPs) that are used to represent real-world concepts and entities. The class represents a group of objects having similar properties and behavior, or in other words, we can say that a class is a blueprint for objects, wh 11 min read Abstract Class in JavaIn Java, abstract class is declared with the abstract keyword. It may have both abstract and non-abstract methods(methods with bodies). An abstract is a Java modifier applicable for classes and methods in Java but not for Variables. In this article, we will learn the use of abstract classes in Java. 10 min read Singleton Method Design Pattern in JavaIn object-oriented programming, a Java singleton class is a class that can have only one object (an instance of the class) at a time. After the first time, if we try to instantiate the Java Singleton classes, the new variable also points to the first instance created. So, whatever modifications we d 7 min read Java InterfaceAn Interface in Java programming language is defined as an abstract type used to specify the behaviour of a class. An interface in Java is a blueprint of a behaviour. A Java interface contains static constants and abstract methods. Key Properties of Interface:The interface in Java is a mechanism to 12 min read Encapsulation in JavaIn Java, encapsulation is one of the coret concept of Object Oriented Programming (OOP) in which we bind the data members and methods into a single unit. Encapsulation is used to hide the implementation part and show the functionality for better readability and usability. The following are important 10 min read Inheritance in JavaJava Inheritance is a fundamental concept in OOP(Object-Oriented Programming). It is the mechanism in Java by which one class is allowed to inherit the features(fields and methods) of another class. In Java, Inheritance means creating new classes based on existing ones. A class that inherits from an 13 min read Abstraction in JavaAbstraction in Java is the process of hiding the implementation details and only showing the essential details or features to the user. It allows to focus on what an object does rather than how it does it. The unnecessary details are not displayed to the user.Key features of abstraction:Abstraction 10 min read Difference Between Data Hiding and Abstraction in JavaAbstraction Is hiding the internal implementation and just highlight the set of services. It is achieved by using the abstract class and interfaces and further implementing the same. Only necessarily characteristics of an object that differentiates it from all other objects. Only the important detai 6 min read Polymorphism in JavaPolymorphism in Java is one of the core concepts in object-oriented programming (OOP) that allows objects to behave differently based on their specific class type. The word polymorphism means having many forms, and it comes from the Greek words poly (many) and morph (forms), this means one entity ca 7 min read Method Overloading in JavaIn Java, Method Overloading allows us to define multiple methods with the same name but different parameters within a class. This difference may include:The number of parametersThe types of parametersThe order of parametersMethod overloading in Java is also known as Compile-time Polymorphism, Static 10 min read Overriding in JavaOverriding in Java occurs when a subclass or child class implements a method that is already defined in the superclass or base class. When a subclass provides its own version of a method that is already defined in its superclass, we call it method overriding. The subclass method must match the paren 15 min read Super Keyword in JavaThe super keyword in Java is a reference variable that is used to refer to the parent class when we are working with objects. You need to know the basics of Inheritance and Polymorphism to understand the Java super keyword. The Keyword "super" came into the picture with the concept of Inheritance. I 7 min read Java this KeywordIn Java, "this" is a reference variable that refers to the current object, or can be said "this" in Java is a keyword that refers to the current object instance. It is mainly used to,Call current class methods and fieldsTo pass an instance of the current class as a parameterTo differentiate between 6 min read static Keyword in JavaThe static keyword in Java is mainly used for memory management, allowing variables and methods to belong to the class itself rather than individual instances. The static keyword is used to share the same variable or method of a given class. The users can apply static keywords with variables, method 9 min read Access Modifiers in JavaIn Java, access modifiers are essential tools that define how the members of a class, like variables, methods, and even the class itself can be accessed from other parts of our program. They are an important part of building secure and modular code when designing large applications. Understanding de 7 min read Java Methods ProgramsJava main() Method - public static void main(String[] args)Java's main() method is the starting point from where the JVM starts the execution of a Java program. JVM will not execute the code if the program is missing the main method. Hence, it is one of the most important methods of Java, and having a proper understanding of it is very important.The Java co 6 min read Difference between static and non-static method in JavaA static method is a method that belongs to a class, but it does not belong to an instance of that class and this method can be called without the instance or object of that class. Every method in java defaults to a non-static method without static keyword preceding it. Non-static methods can access 6 min read HashTable forEach() method in Java with ExamplesThe forEach(BiConsumer) method of Hashtable class perform the BiConsumer operation on each entry of hashtable until all entries have been processed or the action throws an exception. The BiConsumer operation is a function operation of key-value pair of hashtable performed in the order of iteration. 2 min read StringBuilder toString() method in Java with ExamplesThe toString() method of the StringBuilder class is the inbuilt method used to return a string representing the data contained by StringBuilder Object. A new String object is created and initialized to get the character sequence from this StringBuilder object and then String is returned by toString( 3 min read StringBuffer codePointAt() method in Java with ExamplesThe codePointAt() method of StringBuffer class returns a character Unicode point at that index in sequence contained by StringBuffer. This method returns the “Unicodenumber†of the character at that index. Value of index must be lie between 0 to length-1. If the char value present at the given index 2 min read How compare() method works in JavaPrerequisite: Comparator Interface in Java, TreeSet in JavaThe compare() method in Java compares two class specific objects (x, y) given as parameters. It returns the value: 0: if (x==y)-1: if (x < y)1: if (x > y)Syntax:  public int compare(Object obj1, Object obj2)where obj1 and obj2 are th 3 min read Short equals() method in Java with ExamplesThe equals() method of Short class is a built in method in Java which is used to compare the equality given Object with the instance of Short invoking the equals() method. Syntax ShortObject.equals(Object a) Parameters: It takes an Object type object a as input which is to be compared with the insta 2 min read Difference Between next() and hasNext() Method in Java CollectionsIn Java, objects are stored dynamically using objects. Now in order to traverse across these objects is done using a for-each loop, iterators, and comparators. Here will be discussing iterators. The iterator interface allows visiting elements in containers one by one which indirectly signifies retri 3 min read What does start() function do in multithreading in Java?We have discussed that Java threads are typically created using one of the two methods : (1) Extending thread class. (2) Implementing RunnableIn both the approaches, we override the run() function, but we start a thread by calling the start() function. So why don't we directly call the overridden ru 2 min read Java Thread.start() vs Thread.run() MethodIn Java's multi-threading concept, start() and run() are the two most important methods. In this article, we will learn the main differences between Thread.start() and Thread.run() in Java. Thread.start() vs Thread.run() MethodThread.start()Thread.run()Creates a new thread and the run() method is ex 4 min read Java Searching ProgramsJava Program for Linear SearchLinear Search is the simplest searching algorithm that checks each element sequentially until a match is found. It is good for unsorted arrays and small datasets.Given an array a[] of n elements, write a function to search for a given element x in a[] and return the index of the element where it is 2 min read Binary Search in JavaBinary search is a highly efficient searching algorithm used when the input is sorted. It works by repeatedly dividing the search range in half, reducing the number of comparisons needed compared to a linear search. Here, we are focusing on finding the middle element that acts as a reference frame t 6 min read Java Program To Recursively Linearly Search An Element In An ArrayGiven an array arr[] of n elements, write a recursive function to search for a given element x in the given array arr[]. If the element is found, return its index otherwise, return -1.Input/Output Example:Input : arr[] = {25, 60, 18, 3, 10}, Element to be searched x = 3Output : 3 (index )Input : arr 3 min read Java 1-D Array ProgramsCheck If a Value is Present in an Array in JavaGiven an array of Integers and a key element. Our task is to check whether the key element is present in the array. If the element (key) is present in the array, return true; otherwise, return false.Example: Input: arr[] = [3, 5, 7, 2, 6, 10], key = 7Output: Is 7 present in the array: trueInput: arr 8 min read Java Program to Find Largest Element in an ArrayFinding the largest element in an array is a common programming task. There are multiple approaches to solve it. In this article, we will explore four practical approaches one by one to solve this in Java.Example Input/Output:Input: arr = { 1, 2, 3, 4, 5}Output: 5Input: arr = { 10, 3, 5, 7, 2, 12}Ou 4 min read Arrays.sort() in JavaThe Arrays.sort() method is used for sorting the elements in an Array. It has two main variations: Sorting the entire array (it may be an integer or character array) Sorting a specific range by passing the starting and ending indices.Below is a simple example that uses the sort() method to arrange a 6 min read Java Program to Sort the Elements of an Array in Descending OrderHere, we will sort the array in descending order to arrange elements from largest to smallest. The simple solution is to use Collections.reverseOrder() method. Another way is sorting in ascending order and reversing.1. Using Collections.reverseOrder()In this example, we will use Collections.reverseO 2 min read Java Program to Sort the Elements of an Array in Ascending OrderHere, we will sort the array in ascending order to arrange elements from smallest to largest, i.e., ascending order. So the easy solution is that we can use the Array.sort method. We can also sort the array using Bubble sort.1. Using Arrays.sort() MethodIn this example, we will use the Arrays.sort() 2 min read Remove duplicates from Sorted ArrayGiven a sorted array arr[] of size n, the goal is to rearrange the array so that all distinct elements appear at the beginning in sorted order. Additionally, return the length of this distinct sorted subarray.Note: The elements after the distinct ones can be in any order and hold any value, as they 7 min read Java Program to Merge Two ArraysIn Java, merging two arrays is a good programming question. We have given two arrays, and our task is to merge them, and after merging, we need to put the result back into another array. In this article, we are going to discuss different ways we can use to merge two arrays in Java.Let's now see the 5 min read Java Program to Check if two Arrays are Equal or notIn Java, comparing two arrays means checking if they have the same length and identical elements. This checking process ensures that both arrays are equivalent in terms of content and structure.Example:In Java, the simplest way to check if two arrays are equal in Java is by using the built-in Arrays 3 min read Remove all Occurrences of an Element from Array in JavaIn Java, removing all occurences of a given element from an array can be done using different approaches that are,Naive approach using array copyJava 8 StreamsUsing ArrayList.removeAll()Using List.removeIf()Problem Stament: Given an array and a key, the task is to remove all occurrences of the speci 5 min read Java Program to Find Common Elements Between Two ArraysGiven two arrays and our task is to find their common elements. Examples:Input: Array1 = ["Article", "for", "Geeks", "for", "Geeks"], Array2 = ["Article", "Geeks", "Geeks"]Output: [Article, Geeks]Input: Array1 = ["a", "b", "c", "d", "e", "f"], Array2 = ["b", "d", "e", "h", "g", "c"]Output: [b, c, d, 4 min read Array Copy in JavaIn Java, copying an array can be done in several ways, depending on our needs such as shallow copy or deep copy. In this article, we will learn different methods to copy arrays in Java.Example:Assigning one array to another is an incorrect approach to copying arrays. It only creates a reference to t 6 min read Java Program to Left Rotate the Elements of an ArrayIn Java, left rotation of an array involves shifting its elements to the left by a given number of positions, with the first elements moving around to the end. There are different ways to left rotate the elements of an array in Java.Example: We can use a temporary array to rotate the array left by " 5 min read Java 2-D Arrays (Matrix) ProgramsPrint a 2D Array or Matrix in JavaIn this article, we will learn to Print 2 Dimensional Matrix. 2D-Matrix or Array is a combination of Multiple 1 Dimensional Arrays. In this article we cover different methods to print 2D Array. When we print each element of the 2D array we have to iterate each element so the minimum time complexity 4 min read Java Program to Add two MatricesGiven two matrices A and B of the same size, the task is to add them in Java. Examples: Input: A[][] = {{1, 2}, {3, 4}} B[][] = {{1, 1}, {1, 1}} Output: {{2, 3}, {4, 5}} Input: A[][] = {{2, 4}, {3, 4}} B[][] = {{1, 2}, {1, 3}} Output: {{3, 6}, {4, 7}}Program to Add Two Matrices in JavaFollow the Ste 2 min read Sorting a 2D Array according to values in any given column in JavaWe are given a 2D array of order N X M and a column number K ( 1<=K<=m). Our task is to sort the 2D array according to values in Column K.Examples:Input: If our 2D array is given as (Order 4X4) 39 27 11 42 10 93 91 90 54 78 56 89 24 64 20 65Sorting it by values in column 3 Output: 39 27 11 422 3 min read Java Program to Check if two Arrays are Equal or notIn Java, comparing two arrays means checking if they have the same length and identical elements. This checking process ensures that both arrays are equivalent in terms of content and structure.Example:In Java, the simplest way to check if two arrays are equal in Java is by using the built-in Arrays 3 min read Java Program to Find Transpose of MatrixTranspose of a matrix is obtained by changing rows to columns and columns to rows. In other words, the transpose of A[ ][ ] is obtained by changing A[i][j] to A[j][i]. Example of First Transpose of MatrixInput: [ [ 1 , 2 , 3 ] , [ 4 , 5 , 6 ] , [ 7 , 8 , 9 ] ]Output: [ [ 1 , 4 , 7 ] , [ 2 , 5 , 8 ] 5 min read Java Program to Find the Determinant of a MatrixThe determinant of a matrix is a special calculated value that can only be calculated if the matrix has same number of rows and columns (square matrix). It is helpful in determining the system of linear equations, image processing, and determining whether the matrix is singular or non-singular.In th 5 min read Java Program to Find the Normal and Trace of a MatrixIn Java, when we work with matrices, there are two main concepts, and these concepts are Trace and Normal of a matrix. In this article, we will learn how to calculate them and discuss how to implement them in code. Before moving further, let's first understand what a matrix is. What is a Matrix?A ma 3 min read Java Program to Print Boundary Elements of the MatrixIn this article, we are going to learn how to print only the boundary elements of a given matrix in Java. Boundary elements mean the elements from the first row, last row, first column, and last column.Example:Input : 1 2 3 4 5 6 7 8 9Output: 1 2 3 4 6 7 8 9Now, let's understand the approach we are 3 min read Java Program to Rotate Matrix ElementsA matrix is simply a two-dimensional array. So, the goal is to deal with fixed indices at which elements are present and to perform operations on indexes such that elements on the addressed should be swapped in such a manner that it should look out as the matrix is rotated.For a given matrix, the ta 6 min read Java Program to Compute the Sum of Diagonals of a MatrixFor a given 2D square matrix of size N*N, our task is to find the sum of elements in the Principal and Secondary diagonals. For example, analyze the following 4 × 4 input matrix.m00 m01 m02 m03m10 m11 m12 m13m20 m21 m22 m23m30 m31 m32 m33Basic Input/Output:Input 1: 6 7 3 4 8 9 2 1 1 2 9 6 6 5 7 2Out 4 min read Java Program to Interchange Elements of First and Last in a Matrix Across RowsFor a given 4 × 4 matrix, the task is to interchange the elements of the first and last rows and then return the resultant matrix. Illustration: Input 1: 1 1 5 0 2 3 7 2 8 9 1 3 6 7 8 2 Output 1: 6 7 8 2 2 3 7 2 8 9 1 3 1 1 5 0 Input 2: 7 8 9 10 11 13 14 1 15 7 12 22 11 21 30 1 Output 2: 11 21 30 1 3 min read Java Program to Interchange Elements of First and Last in a Matrix Across ColumnsFor a given 4 x 4 matrix, the task is to interchange the elements of the first and last columns and then return the resultant matrix.Example Test Case for the ProblemInput : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Output : 4 2 3 1 8 6 7 5 12 10 11 9 16 14 15 13 Implementation of Interchange Elements o 2 min read Java String ProgramsJava Program to Get a Character from a StringGiven a String str, the task is to get a specific character from that String at a specific index. Examples:Input: str = "Geeks", index = 2Output: eInput: str = "GeeksForGeeks", index = 5Output: F Below are various ways to do so: Using String.charAt() method: Get the string and the indexGet the speci 5 min read Replace a character at a specific index in a String in JavaIn Java, here we are given a string, the task is to replace a character at a specific index in this string. Examples of Replacing Characters in a StringInput: String = "Geeks Gor Geeks", index = 6, ch = 'F'Output: "Geeks For Geeks."Input: String = "Geeks", index = 0, ch = 'g'Output: "geeks"Methods t 3 min read Reverse a String in JavaIn Java, reversing a string means reordering the string characters from the last to the first position. Reversing a string is a common task in many Java applications and can be achieved using different approaches. In this article, we will discuss multiple approaches to reverse a string in Java with 7 min read Java Program to Reverse a String using StackThe Stack is a linear data structure that follows the LIFO(Last In First Out) principle, i.e, the element inserted at the last is the element to come out first. Approach: Push the character one by one into the Stack of datatype character.Pop the character one by one from the Stack until the stack be 2 min read Sort a String in Java (2 different ways)The string class doesn't have any method that directly sorts a string, but we can sort a string by applying other methods one after another. The string is a sequence of characters. In java, objects of String are immutable which means a constant and cannot be changed once created. Creating a String T 6 min read Swapping Pairs of Characters in a String in JavaGiven string str, the task is to write a Java program to swap the pairs of characters of a string. If the string contains an odd number of characters then the last character remains as it is. Examples: Input: str = “Javaâ€Output: aJav Explanation: The given string contains even number of characters. 3 min read Check if a given string is Pangram in JavaGiven string str, the task is to write Java Program check whether the given string is a pangram or not. A string is a pangram string if it contains all the character of the alphabets ignoring the case of the alphabets. Examples: Input: str = "Abcdefghijklmnopqrstuvwxyz"Output: YesExplanation: The gi 3 min read Print first letter of each word in a string using regexGiven a string, extract the first letter of each word in it. "Words" are defined as contiguous strings of alphabetic characters i.e. any upper or lower case characters a-z or A-Z. Examples: Input : Geeks for geeksOutput :Gfg Input : United KingdomOutput : UKBelow is the Regular expression to extract 3 min read Java Program to Determine the Unicode Code Point at Given Index in StringASCII is a code that converts the English alphabets to numerics as numeric can convert to the assembly language which our computer understands. For that, we have assigned a number against each character ranging from 0 to 127. Alphabets are case-sensitive lowercase and uppercase are treated different 5 min read Remove Leading Zeros From String in JavaGiven a string of digits, remove leading zeros from it.Illustrations: Input : 00000123569Output: 123569Input: 000012356090Output: 12356090Approach: We use the StringBuffer class as Strings are immutable.Count leading zeros by iterating string using charAt(i) and checking for 0 at the "i" th indices. 3 min read Compare two Strings in JavaString in Java are immutable sequences of characters. Comparing strings is the most common task in different scenarios such as input validation or searching algorithms. In this article, we will learn multiple ways to compare two strings in Java with simple examples.Example:To compare two strings in 4 min read Compare two strings lexicographically in JavaIn this article, we will discuss how we can compare two strings lexicographically in Java. One solution is to use Java compareTo() method. The method compareTo() is used for comparing two strings lexicographically in Java. Each character of both the strings is converted into a Unicode value for comp 3 min read Java program to print Even length words in a StringGiven a string s, write a Java program to print all words with even length in the given string. Example to print even length words in a String Input: s = "i am Geeks for Geeks and a Geek" Output: am GeekExample:Java// Java program to print // even length words in a string class GfG { public static v 3 min read Insert a String into another String in JavaGiven a String, the task is to insert another string in between the given String at a particular specified index in Java. Examples: Input: originalString = "GeeksGeeks", stringToBeInserted = "For", index = 4 Output: "GeeksForGeeks" Input: originalString = "Computer Portal", stringToBeInserted = "Sci 4 min read Split a String into a Number of Substrings in JavaGiven a String, the task it to split the String into a number of substrings. A String in java can be of 0 or more characters. Examples : (a) "" is a String in java with 0 character (b) "d" is a String in java with 1 character (c) "This is a sentence." is a string with 19 characters. Substring: A Str 5 min read Like