Swapping two numbers

Two numbers can be swapped or interchanged. It means first number will become second and second number will become first.

For example

1. a = 20, b = 30  
2. After swapping,  
3. a = 30, b = 20  

There are two methods for swapping:

• By using third variable.
• Without using third variable.

Swapping Using Third Variable

Swap two numbers 45 and 78 using a third variable.

2. Objects in PHP | Build a CMS using OOP PHP tutorial MVC [2020]

Example:

1. <?php  
2. $a = 45;  
3. $b = 78;  
4. // Swapping Logic  
5. $third = $a;  
6. $a = $b;  
7. $b = $third;  
8. echo "After swapping:<br><br>";  
9. echo "a =".$a."  b=".$b;  
10. ?>  

Output:

Swapping Without using Third Variable

Swap two numbers without using a third variable is done in two ways:

• Using arithmetic operation + and ?
• Using arithmetic operation * and /

Example for (+ and -):

1. <?php  
2. $a=234;  
3. $b=345;  
4. //using arithmetic operation  
5. $a=$a+$b;  
6. $b=$a-$b;  
7. $a=$a-$b;  
8. echo "Value of a: $a</br>";  
9. echo "Value of b: $b</br>";  
10. ?>  

Output:

Example for (* and /):

1. <?php  
2. $a=234;  
3. $b=345;  
4. // using arithmetic operation  
5. $a=$a*$b;  
6. $b=$a/$b;  
7. $a=$a/$b;  
8. echo "Value of a: $a</br>";  
9. echo "Value of b: $b</br>";  
10. ?>  

Output: