Swapping Program in Java

The swapping program in Java is used to interchange the values of the two variables. For example, if X = 12 and Y = 24, then the execution of the swapping program will interchange their values, i.e., X = 24 and Y = 12.

There are two approaches to interchange values between the two variables.

• Using Third Variable

Using Third Variable

The different steps required to interchange values between the given variables are mentioned below.

STEP 1: Define three variables x, y, and z.

STEP 2: Assign values to any of the two variables. Let’s assign the values in x and y.

STEP 3: Print the values of x and y.

STEP 4: Assign the value of x to the third variable z, i.e., z = x; Now, x and z both contain the same value.

STEP 5: Assign the value of y in x, i.e., x = y;

STEP 6: Assign the value of z in y, i.e., y = z;

STEP 7: Again, print the values of x and y. The values swapped.

The following Java program uses the above steps to interchange the values of the two variables.

Filename: SwappingExample.java

Output 1:

Output 2:

Explanation: In the above program, we are providing values to the variables i and j. The variable k acts as the third variable. On the basis of the above-mentioned steps, we are doing accomplishing the swapping of numbers between the variables i and j.

In this approach, the usage of the extra variable is not required. We do only the addition and subtraction operations on both numbers in such a way that numbers contained in both the variables get swapped.

There are the following steps to swap the two numbers using addition and subtraction.

STEP 1: Define two variables, a and b.

STEP 2: Assign values to the variables.

STEP 3: Display values of the variables a and b.

STEP 4: Update the value of variable a by doing the addition operation, i.e., a = a + b

STEP 5: Update the value of variable b by doing the subtraction operation, i.e., b = a – b

STEP 6: Again, update the value of the variable a by doing the subtraction operation, i.e., a = a – b

STEP 7: Again, display the values of variables a and b. This time values of the variables a and b get swapped.

The following Java program illustrates the above-written steps.

Filename: SwappingExample1.java

Output1:

Output2:

Explanation: In the code, we are providing values to the variables a and b. Then, we are swapping the values of variables a and b using the steps defined above. Finally, we are displaying the result.

Note: The second approach is more important than the first one. The second approach is usually asked in interviews.