How does the order of function calls and returns impact the execution of nested functions in PHP?

The order of function calls and returns can impact the execution of nested functions in PHP because functions are executed in the order they are called. If a function is called before it is defined, PHP will throw an error. To avoid this issue, make sure to define functions before calling them in your code.

<?php

// Define the nested functions first
function innerFunction() {
    return "Inner function called.";
}

function outerFunction() {
    return innerFunction();
}

// Call the outer function after defining all functions
echo outerFunction();

?>