PHP: Conditions inside the loop body

Both the loop body and function body are places where statements are executed. So we can use all the things we've already learned in it, such as conditionals.

Imagine a function that counts how many times a letter appears in a sentence. Here's how it might work:

<?php

countChars('Fear cuts deeper than swords.', 'e'); // 4
// If there are no matches, the result is 0
countChars('Sansa', 'y'); // 0

Before examining its contents, answer these questions:

• Is this an aggregation operation?
• What'll be the test condition for whether or not the character occurs?

<?php

function countChars($str, $char)
{
    $i = 0;
    $count = 0;
    while ($i < strlen($str)) {
        if ($str[$i] === $char) {
            // Count only matching characters
            $count = $count + 1;
        }
        // The counter increases in any case
        $i = $i + 1;
    }

    return $count;
}

This is an aggregating task. Despite the fact that it doesn't count all the characters, you still have to analyze each character to calculate the amount itself.

A key feature of this loop is the condition inside its body. The $count variable is only incremented when the current character in question is the same as the expected one.

Apart from that, it's a generic aggregation function that returns the number of required characters.

Instructions

The function from the theory is case-sensitive. This means that A and a from its perspective are different characters. Write a version of this function that isn't case-sensitive:

<?php

countChars('HexlEt', 'e'); // 2
countChars('HexlEt', 'E'); // 2