JuniorTheoryCommon

What does the program print?

PHP

<?php

function double($x)
{
    return $x * 2;
}

echo double(double(5)) + 1, "\n";

Expecting 11, as if only the inner call ran: its result 10 becomes the argument of the outer call, so double runs twice and returns 20 before + 1.
Expecting 22: + 1 stands outside the parentheses, so it is added to what the outer call returns, not to the outer call's argument.

What would double(double(5) + 1) return, and in what order would it be computed?
Why may the call to double stand above the function double line in the file?

JuniorTheoryCommon

PHP

<?php

function double($x)
{
    return $x * 2;
}

echo double(double(5)) + 1, "\n";

Expecting 11, as if only the inner call ran: its result 10 becomes the argument of the outer call, so double runs twice and returns 20 before + 1.
Expecting 22: + 1 stands outside the parentheses, so it is added to what the outer call returns, not to the outer call's argument.

What would double(double(5) + 1) return, and in what order would it be computed?
Why may the call to double stand above the function double line in the file?