How to Swap Variables

When solving programming problems, you often need to swap the values of two variables. There are two common approaches for swapping values in Java:

Option 1: Swapping values using a temporary variable

You can introduce a temporary variable to hold one of the values temporarily during the exchange:

int tmp = a;
a = b;
b = tmp;

Example:

public class SwapExample1 {
    public static void main(String[] args) {
        int a = 3;
        int b = 5;

        int tmp = a;
        a = b;
        b = tmp;

        System.out.println("a = " + a);
        System.out.println("b = " + b);
    }
}

Option 2: Swapping values without using a temporary variable

This method uses arithmetic operations (addition and subtraction) to perform the swap without a third variable:

a = a + b;
b = a - b;
a = a - b;

Example:

public class SwapExample2 {
    public static void main(String[] args) {
        int a = 3;
        int b = 5;

        a = a + b; // a = 8, b = 5
        b = a - b; // a = 8, b = 3
        a = a - b; // a = 5, b = 3

        System.out.println("a = " + a);
        System.out.println("b = " + b);
    }
}

Note: The arithmetic method works only for numeric types and may cause integer overflow with very large values. The temporary variable method is safer and more readable in most cases.