There are several methods of doing this. Below are 2 solutions:
Method 1: Using Addition and Subtraction
public class SwapNumbers
{
public static void main(String args[])
{
int num1 = 10, num2 = 20;
System.out.println("First Number: "+num1);
System.out.println("Second Number: "+num2);
num1 = num1 + num2;
num2 = num1 - num2;
num1 = num1 - num2;
System.out.println("First Number: "+num1);
System.out.println("Second Number: "+num2);
}
}
Method 2: Using Multiplication and Division
public class SwapNumbers
{
public static void main(String args[])
{
int num1 = 10, num2 = 20;
System.out.println("First Number: "+num1);
System.out.println("Second Number: "+num2);
num1 = num1 * num2;
num2 = num1 / num2;
num1 = num1 / num2;
System.out.println("First Number: "+num1);
System.out.println("Second Number: "+num2);
}
}