A Program to check if strings are rotations of each other or not

Given a string s1 and a string s2, write a snippet to say whether s2 is a rotation of s1? 
(eg given s1 = ABCD and s2 = CDAB, return true, given s1 = ABCD, and s2 = ACBD , return false)

Algorithm: areRotations(str1, str2)

   1. Create a temp string and store concatenation of str1 to
      str1 in temp.
                         temp = str1.str1
   2. If str2 is a substring of temp then str1 and str2 are 
      rotations of each other.

   Example:                 
                    str1 = "ABACD"
                    str2 = "CDABA"

    temp = str1.str1 = "ABACDABACD"
    Since str2 is a substring of temp, str1 and str2 are 
    rotations of each other.

A Program to check if strings are rotations of each other or not: https://www.geeksforgeeks.org/a-program-to-check-if-strings-are-rotations-of-each-other/