用php写带入判断大小的变量

用php怎么写出以下功能 $a=2 $b=3 $c='>='怎么将这三个值带入if()进行判断并输出真假用最简单的代码写一个函数

<?php

function compareValues($a, $b, $c) {

if ($c == '==') {
    return $a == $b;
} elseif ($c == '!=') {
    return $a != $b;
} elseif ($c == '>') {
    return $a > $b;
} elseif ($c == '>=') {
    return $a >= $b;
} elseif ($c == '<') {
    return $a < $b;
} elseif ($c == '<=') {
    return $a <= $b;
} else {
    return "无效的比较运算符";
}

}

$a = 2;
$b = 3;
$c = '>=';

$result = compareValues($a, $b, $c);

if ($result === true) {

echo "真";

} elseif ($result === false) {

echo "假";

} else {

echo $result;

}

?>