How can improper variable naming conventions impact the functionality of PHP code?

Improper variable naming conventions can impact the functionality of PHP code by making the code harder to read and understand, leading to potential errors and confusion. To solve this issue, it is important to follow naming conventions such as using descriptive names, avoiding reserved keywords, and using camelCase or snake_case for variable names.

// Improper variable naming
$my_var = 10;
$myVar = 20;
$myVar1 = $my_var + $myVar;

// Proper variable naming
$firstNumber = 10;
$secondNumber = 20;
$sum = $firstNumber + $secondNumber;