Convert Binary to Octal in Java

Binary Number ? There are many types of number systems depending upon the base value. Binary numbers are one of them. The Binary number is basically represented by two digits i.e. one (1) and zero (0). The binary numbers are expressed as base-2 in the numeral system.

Octal Number ? Octal number is also one of the number systems available. The octal number is represented with 8 digits which is from 0 to 7(0, 1, 2, 3... 7). The Octal numbers are expressed as base-8 in the numeral system.

Here we are converting the Binary number to an octal number but for this, we have to first convert the binary number into a decimal number so that further we can convert that decimal number into an octal number using the toOctalString() method.

Binary Number ? Decimal Number ? Octal Number

The toOctalString() method is a built-in function of the Integer class.

Syntax

public static String toOctalString(int i)

Problem Statement

Write a program in Java to convert binary numbers to octal numbers ?

Input-1

Input Binary number is 101011.

Output-1

By converting into decimal = 43.
Now converting it to octal = 53

Input-2

Input Binary number is 1111111.

Output-2

By converting into decimal = 127
Now converting it to octal = 177

Input-3

Input Binary number is 11001100.

Output-3

By converting into decimal = 204.
Now converting it to octal = 314.

Approaches to convert binary to octal

We have provided the solution in different approaches ?

• By using the user-defined method with Static Input Values.
• By using the user-defined method with User Input Values.

Approach-1: By Using User Defined Method with Static Input Value

In this approach, we declare a long variable initialize it with a binary number in the program, and pass this number as a parameter in a user-defined method, then inside the method by using the algorithm, we can convert the binary number into an octal number.

• Start
• Import java.util.* and define the Main class.
• Declare a long variable binary with a static value.
• Convert Binary to Decimal then convert Decimal to Octal and print the values.
• Stop

Example

Below is an example of converting the binary number into an octal number using the static input method -

import java.util.*;
public class Main {
   public static void main(String[] args){
      long binary=1010;
      binToDec(binary);
   }
   public static void binToDec(long binaryNumber){
      int decNum = 0, i = 0;
      while (binaryNumber > 0) {
         decNum += Math.pow(2, i++) * (binaryNumber % 10);
         binaryNumber /= 10;
      }
      System.out.println("In Decimal="+decNum);
      decToOct(decNum);
   }
   public static void decToOct(long decNum){
      String octalString = Long.toOctalString(decNum);
      int octalNumber = Integer.parseInt(octalString);
      System.out.println("In octal="+octalNumber);
   }
}

Output

In Decimal=10
In octal=12

Approach-2: By Using User Defined Method with User Input Value

In this approach, we declare a binary input number and pass this number as a parameter in a user-defined method, then inside the method by using the algorithm, we can convert the binary number into a hexadecimal number.

• Start
• Import java.util.* and define the Main class.
  
• Take User Input for Binary Number.
• Call User-Defined Method for Conversion.
• Convert Binary to Decimal then convert Decimal to Octal and print the values.
• Stop.

Example

Below is an example of converting the binary number into an octal number using a user-defined method -

import java.util.*;
public class Main {
   public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      System.out.print("Enter a binary number: ");
      long binary=sc.nextLong();
      binToDec(binary);
   }
   public static void binToDec(long binaryNumber){
      int decNum = 0, i = 0;
      while (binaryNumber > 0) {
         decNum += Math.pow(2, i++) * (binaryNumber % 10);
         binaryNumber /= 10;
      }
      System.out.println("In Decimal="+decNum);
      decToOct(decNum);
   }
   public static void decToOct(long decNum){
      String octalString = Long.toOctalString(decNum);
      int octalNumber = Integer.parseInt(octalString);
      System.out.println("In octal="+octalNumber);
   }
}

Output

Enter a binary number: 1111
In Decimal=15
In octal=17

In this article, we explored how to convert binary to octal in Java by using different approaches.