Strnatcmp () function-php Tutorial

The strnatcmp () function strnatcmp () is used to compare the numbers in a string by number.
$ Str1 = "mrsoft1 ";
$ Str2 = "MRSOFT2 ";
Echo strnatcmp ($ str1, $ str2 );
The expected result is-1, and the result is 1. what is the reason?

Reply to discussion (solution)

$ Str1 = "mrsoft1"; $ str2 = "MRSOFT2"; echo strnatcmp ($ str1, $ str2); // 1 because m is larger than M $ str1 = "mrsoft1 "; $ str2 = "mrsoft2"; echo strnatcmp ($ str1, $ str2); //-1 for $ str1 = "mrsoft11"; $ str2 = "mrsoft2 "; echo strnatcmp ($ str1, $ str2); // 1 This is the intention that 11 is greater than 2

Previously, I did not understand the function properly. I thought that I only compared the numbers in the string and ignored the ASCII value of the characters.
Thank you for your answers.