In PHP this function is used for string comparisons using a "natural order" algorithm.In the natural order algorithm 2 is greater than 10, whereas in normal one 10 is larger thar 2.

    strnatcmp(string1,string2)

In the above syntax "string1" ,"string2" are the two string to compare.The function returns "0" if both strings are equal, returns a value "<0" if string1 is less than string2, returns a value ">0" if string1 is greater than string2.

    <?php
    echo strnatcasecmp("2Hi","10Hi");
    echo "<br/>";
    echo strnatcasecmp("10Hi","2Hi");
    ?>

    -1
    1

In the above example both the string are same but the numbers are treated as strings and compared using the natural order algorithm display results.