Perl - decrement operator

The decrement (--) is an unary operator in Perl and hence acts upon a single operand to produce a new value. It has two variant:

• Pre-decrement: Decreases the value of the operand by 1, then returns the operand.
• Post-decrement: Returns the operand, then decreases the value of the operand by 1.

Example: Pre-decrement operator

The example below describes the usage of pre-decrement operator.

$x = 10;
$y = 20;
$z;

#below expression is equivalent to
#x = x - 1; z = x + y;
$z = --$x + $y;    

#Displaying the result
print("x = $x \n");
print("y = $y \n");
print("z = $z \n");

The output of the above code will be:

x = 9
y = 20
z = 29

Example: Post-decrement operator

The example below describes the usage of post-decrement operator.

$x = 10;
$y = 20;
$z;

#below expression is equivalent to
#z = x + y; x = x - 1;
$z = $x-- + $y;    

#Displaying the result
print("x = $x \n");
print("y = $y \n");
print("z = $z \n");

The output of the above code will be:

x = 9
y = 20
z = 30