strcmp expression function

Compares two strings.

• Returns a negative number if s1 is lexicographically less than s2

• Returns a positive number if s1 is lexicographically greater than s2

• Returns 0 if s1 is equal to s2

This function is case-sensitive. For case-insensitive comparison, use strcasecmp.

strcmp("abc", "xyz") = -1

strcmp("xyz, "abc") = 1

strcmp("abc", "abc") = 0