Call by Value in PHP

In PHP, function arguments are typically passed by value by default. This means that when you pass a variable to a function as an argument, a copy of the variable's value is made, and any changes made to the parameter inside the function do not affect the original variable outside the function.

Here's an example to illustrate call by value in PHP:

function increment($num) {
    $num++;
    echo "Inside function: $num <br>";
}
$num = 5;
increment($num);
echo "Outside function: $num"; // Output: Outside function: 5

In this example

• We define a function called increment() that takes a parameter $num.
• Inside the function, we increment the value of $num by one.
• We then declare a variable $num with the value 5 outside the function.
• We call the increment() function with the variable $num as an argument.
• Inside the function, the value of $num is incremented to 6, but this change does not affect the original variable $num outside the function. So, when we echo the value of $num outside the function, it remains 5.

In summary, when you pass a variable to a function as an argument in PHP, the function receives a copy of the variable's value rather than the variable itself. Therefore, any modifications made to the parameter inside the function do not affect the original variable outside the function. This behavior is known as call by value.