Nested If Else Statement in Programming

Nested If Else Statements are a fundamental concept in programming. They allow us to create more complex decision-making structures by placing one if else statement inside another. In this article, we will discuss the Nested if else statement.

What is Nested If Else Statement?

Nested if else statements allow for more complex decision-making within the program. You can nest if else statements with other if else statements, creating conditions at multiple levels.

Syntax of Nested If Else Statement:

if (condition1) {
// Code block for condition1 being true
if (condition2) {
// Code block for condition1 and condition2 both being true
} else {
// Code block for condition1 being true and condition2 being false
}
} else {
// Code block for condition1 being false
}

Nested If Else Statement in C:

Here are the implementation of Nested if else statement in C language:

#include <stdio.h>

int main() {
    // Declare and initialize the variable num
    int num = 10;

    // Outer if-else statement to check if num is greater than 0
    if (num > 0) {
        printf("Number is positive.\n");

        // Nested if-else statement to check if num is even or odd
        if (num % 2 == 0) {
            printf("Number is even.\n");
        } else {
            printf("Number is odd.\n");
        }

    } else {
        // Execute if num is not greater than 0
        printf("Number is non-positive.\n");
    }

    return 0;
}

Number is positive.
Number is even.

Nested If Else Statement in C++:

Here are the implementation of Nested if else statement in C++ language:

#include <iostream>
using namespace std;

int main() {
    // Declare and initialize the variable num
    int num = 10;

    // Outer if-else statement to check if num is greater than 0
    if (num > 0) {
        cout << "Number is positive." << endl;

        // Nested if-else statement to check if num is even or odd
        if (num % 2 == 0) {
            cout << "Number is even." << endl;
        } else {
            cout << "Number is odd." << endl;
        }

    } else {
        // Execute if num is not greater than 0
        cout << "Number is non-positive." << endl;
    }

    return 0;
}

Number is positive.
Number is even.

Nested If Else Statement in Java:

Here are the implementation of Nested if else statement in java language:

public class Main {
    public static void main(String[] args) {
        // Declare and initialize the variable num
        int num = 10;

        // Outer if-else statement to check if num is greater than 0
        if (num > 0) {
            System.out.println("Number is positive.");

            // Nested if-else statement to check if num is even or odd
            if (num % 2 == 0) {
                System.out.println("Number is even.");
            } else {
                System.out.println("Number is odd.");
            }

        } else {
            // Execute if num is not greater than 0
            System.out.println("Number is non-positive.");
        }
    }
}

Number is positive.
Number is even.

Nested If Else Statement in Python:

Here are the implementation of Nested if else statement in python language:

# Declare and initialize the variable num
num = 10

# Outer if-else statement to check if num is greater than 0
if num > 0:
    print("Number is positive.")

    # Nested if-else statement to check if num is even or odd
    if num % 2 == 0:
        print("Number is even.")
    else:
        print("Number is odd.")

else:
    # Execute if num is not greater than 0
    print("Number is non-positive.")

Number is positive.
Number is even.

Nested If Else Statement in C#:

Here are the implementation of Nested if else statement in C# language:

using System;

class Program {
    static void Main(string[] args) {
        // Declare and initialize the variable num
        int num = 10;

        // Outer if-else statement to check if num is greater than 0
        if (num > 0) {
            Console.WriteLine("Number is positive.");

            // Nested if-else statement to check if num is even or odd
            if (num % 2 == 0) {
                Console.WriteLine("Number is even.");
            } else {
                Console.WriteLine("Number is odd.");
            }

        } else {
            // Execute if num is not greater than 0
            Console.WriteLine("Number is non-positive.");
        }
    }
}

Number is positive.
Number is even.

Nested If Else Statement in JavaScript:

Here are the implementation of Nested if else statement in javascript language:

// Declare and initialize the variable num
let num = 10;

// Outer if-else statement to check if num is greater than 0
if (num > 0) {
    console.log("Number is positive.");

    // Nested if-else statement to check if num is even or odd
    if (num % 2 === 0) {
        console.log("Number is even.");
    } else {
        console.log("Number is odd.");
    }

} else {
    // Execute if num is not greater than 0
    console.log("Number is non-positive.");
}

Number is positive.
Number is even.

Best Practices of Nested If Else Statement:

• Keep it Simple: Don't make your if else chains too long or complicated.
• Use Clear Conditions: Use descriptive conditions so anyone reading your code can understand what's happening.
• Avoid Redundancy: Don't repeat the same conditions unnecessarily.
• Exit Early: Use return or break to exit the if else chain as soon as possible.
• Consider Alternatives: Sometimes, using ternary operators or switch-case statements can make your code clearer.
• Add Comments: If your logic is complex, explain it with comments so others (and your future self) can understand.

Use Cases of Nested If Else Statement:

• Grading System: If a student's score is greater than or equal to 90, they get an 'A'. If not, check if it's greater than or equal to 80 for a 'B', and so on.
• Shopping Cart Discounts: If the user is a premium member, apply a 10% discount. If not, check if the total exceeds a certain amount for a 5% discount.
• Authentication and Authorization: If the user's credentials are valid, check their role. Depending on the role, grant access to different parts of the system.
• Weather Forecast: If the temperature is above 30°C, it's hot. If not, check if it's between 20-30°C for a moderate forecast, and so on.
• Game Development: If the player's health is less than or equal to 0, they lose the game. If not, check if they have enough ammo to continue fighting.

Conclusion:

Use nested if else statements in programming when you need to evaluate conditions within other conditions. It helps you handle complex scenarios by branching your code based on various possibilities.