7. Let S be the set of bit strings and Z be the set of integers. Determine if f is the function from S to Z if given a string s

1. f(s) is the position of a 0 bit in s.
2. f(s) is the number of 1 bits in s.
3. f(s) is the smallest integer i such that the ith bit of S is 1 and f(0) = 0 when S is the empty string.