When comparing two strings in PHP, what are the differences between using strcmp() and '=='?

When comparing two strings in PHP, using strcmp() compares the strings based on their ASCII values, returning 0 if they are equal, a negative value if the first string is less than the second, and a positive value if the first string is greater than the second. On the other hand, using '==' directly compares the strings character by character, returning true if they are equal and false if they are not.

$string1 = "hello";
$string2 = "world";

// Using strcmp()
if (strcmp($string1, $string2) === 0) {
    echo "The strings are equal using strcmp()";
} else {
    echo "The strings are not equal using strcmp()";
}

// Using '=='
if ($string1 == $string2) {
    echo "The strings are equal using '=='";
} else {
    echo "The strings are not equal using '=='";
}