Core PHP: Function Parameters (6.2)

Function Parameters

Information can be passed to functions through arguments, which are like variables.
Arguments are specified after the function name, and within the parentheses.
Here, our function takes a number, multiplies it by two, and prints the result:

function multiplyByTwo($number) {
  $answer = $number * 2;
  echo $answer;
}
multiplyByTwo(3);
//Outputs 6

You can add as many arguments as you want, as long as they are separated with commas.

function multiply($num1, $num2) {
  echo $num1 * $num2;
}
multiply(3, 6);
//Outputs 18

When you define a function, the variables that represent the values that will be passed to it for processing are called parameters. However, when you use a function, the value you pass to it is called an argument.