PHPGurukul

Functions In PHP

  • A block of code for specific tasks.
  • Save compile time –only compile once.
  • Reuse many times when needed.
  • Optimize your code.
  • Built-in functions like print(); date();

    • User-defined functions:
    • Function names cannot have spaces.
    • Function name must begin with letter or underscore.

    E.g., call a built-in function abs();

    <?php
    $num=-5;
    $new_num=abs($num);
    echo $new_num;
    ?>

    Declaring a Function

    function function_name(arguments)
    {
    block of codes and statements;
    }
    • You can declare a function below a call to it.
    • May have none, one, or multiple arguments each separated by a comma.
    • Write function name followed by ( ), even if the function doesn’t have any arguments.

    Example-

    <?php
    function print_br($str) {
    print "$str <br>";
    }
    print_br("line1");
    print_br("line2");
    ?>

    Functions – Return Value

    • Functions may have a return value.
    • A return value in a function, returns the value to the function that may be used later on while calling a function.
    • You may need to access the value that the function returns, but you may not need to print it out, that’s why you use a return value for a function.

    Example-Functions – Return Value

    <?php
    function multiply_by_two($value){
    $result=$value*2;
    return $result;
    }
    echo multiply_by_two(7);
    ?>

    Example-Functions – Without Return Value

    <?php
    function multiply_by_two($value){
    $result=$value*2;
    echo $result;
    }
    multiply_by_two(7);
    ?>

    PHP built-in Functions
    Sqrt(); — Take the square root of a number
    Ceil(); — Take ceil of a decimal number
    Floor(); — take the floor of a decimal number
    Max(); — take the max number
    Min(); — take the min number
    Strtolower(); — convert string to lower case
    Strtoupper(); — convert string to upper case

Anuj Kumar

This is Anuj Kumar. I’m a professional web developer with 4+ year experience. I write blogs in my free time. I love to learn new technologies and share with others.
I founded PHPGurukul in September 2015. The main aim of this website to provide PHP, Jquery, MySQL, PHP Oops and other web development tutorials.
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