package hamming

import "errors"

// TestVersion is an exercism thing
const TestVersion = 2

// Distance measures the hamming distance between two sequences
// and returns the number if different bytes and an error value
func Distance(seq1, seq2 string) (int, error) {
	if len(seq1) != len(seq2) {
		return -1, errors.New("Strands must be equal length")
	}
	var ret int
	for i := 0; i < len(seq1); i++ {
		if seq1[i] != seq2[i] {
			ret++
		}
	}
	return ret, nil
}