PHP : Function

/* user-defined fucntion */ function test(){ echo "hello world"; } /* calling user-defined fucntion */ test(); //output hello world /* returning values */ function add() { return 1 + 1; } add(); //output 2

/* passing variable to functions */ function test($string) {           echo "hello ".$string; } test('world'); //output hello world /* returning values */ function add($number) {          return 1 + $number; } add(1); //output 2