Check If Strings are Rotations of Each Other

Given a string s1 and a string s2, write a snippet to say whether s2 is a rotation of s1 Algorithm:

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.