What is the purpose of type conversion and type casting in PHP, and when should it be applied?

Type conversion and type casting in PHP are used to change the data type of a variable from one type to another. Type conversion is done implicitly by PHP when necessary, while type casting is done explicitly by the programmer. Type conversion should be applied when you need to perform operations on variables of different data types or when you want to change the data type of a variable for a specific operation. Type casting should be used when you want to enforce a specific data type for a variable, especially when working with functions or operations that require a specific data type.

// Type Conversion
$number = "10";
$sum = $number + 5; // $number is implicitly converted to integer
echo $sum; // Output: 15

// Type Casting
$number = "10";
$number = (int)$number; // $number is explicitly cast to integer
echo $number; // Output: 10