Here we save the value of 1st variable into a new 3rd variable. Now the 1st variable saves the value of 2nd variable and the 2nd variable saves the value of 3rd variable. In this way the value is exchanged.

*------Do not copy this code, this is just for illustration-------*
Data: lv_var1, lv_var2, lv_var3. "Here we have 3 variables
lv_var1 = 2. "Assinging values to variables
lv_var2 = 5.
* swapping code
lv_var3 = lv_var1. "Saving value of var 1 in var 3
lv_var1 = lv_var2. "Saving value of var 2 in var 1
lv_var2 = lv_var3. "Saving value of var 3 in var 1
*** Now the output will show lv_var1 = 5 and lv_var2  = 2

Swapping without using third variable:

This can be achieved using either addition-subtraction or multiplication-division methods. We will show how in below illustration code:

*------Do not copy this code, this is just for illustration-------*
Data: lv_var1, lv_var2. "Here we have 2 variables
lv_var1 = 2. "Assinging values to variables
lv_var2 = 5.
* swapping code
lv_var1 = lv_var1 + lv_var2 . "Now lv_var1 = 2+5 = 7.
lv_var2 = lv_var1 - lv_var2. "Now lv_var2 = 7-5 = 2.
lv_var1 = lv_var1 - lv_var2. "Now lv_var1 = 7-2 = 5.
*** Now the output will show lv_var1 = 5 and lv_var2  = 2

Similarly using multiplication-division, we will achieve the same.

Now the ABAP program to achieve the swap is shown below:

PARAMETERS : lv_num1(4) type i,
             lv_num2(4) type i.
lv_num1 = lv_num1 + lv_num2.
lv_num2 = lv_num1 - lv_num2.
lv_num1 = lv_num1 - lv_num2.
Write: 'Swapped Values are :', lv_num1, lv_num2.