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# Java Program to Swap Two Numbers Without Using Third or Temporary Variable

###### Tutorialsrack 19/04/2021 Java

In this Java program, you will learn how to swap two numbers without using the third or temporary variables in java. In this program, instead of using a temporary variable, we use simple mathematics calculations to swap the numbers.

### Java Program to Swap Two Numbers Without Using Third or Temporary Variable

##### Java Program to Swap Two Numbers Without Using Third or Temporary Variable
``````//Java Program to Swap Two Numbers Without Using Temporary Variable

public class JavaPrograms {

public static void main(String[] args) {

float first = 5.0f, second = 8.5f;

System.out.println("--Before swap the numbers--");
System.out.println("First number = " + first);
System.out.println("Second number = " + second);

first = first - second;
second = first + second;
first = second - first;

System.out.println("--After swap the numbers--");
System.out.println("First number = " + first);
System.out.println("Second number = " + second);

}
}
``````
##### Output

--Before swap the numbers--

First number = 5.0

Second number = 8.5

--After swap the numbers--

First number = 8.5

Second number = 5.0

### Understand the Program

For the operation, storing (first - second) is important. This is stored in a variable first.

first = first - second;

first = 5.0f - 8.5f

Then, we just add second (24.5f) to this number - calculated first (5.0f - 8.5f) to swap the number.

second = first + second;

second = (5.0f - 8.5f) + 8.5f = 5.0f

Now, the second  variable holds 5.0f (which was the initial value of the first variable). So, we subtract calculated first (5.0f - 8.5f) from swapped second (5.0f) to get the other swapped number.

first = second - first;

first = 5.0f - (5.0f - 8.5f) = 8.5f

Then, the swapped numbers are printed on the screen using `println()`.