Better to use a hash map instead of an array. When iterating the second string, as soon as you see a character without an existing value it's not an anagram. If you finish the second string, check that all values are zero.
This way you only need to check the character values you actually use, and not all 127. It also generalizes trivially to larger character sets.
His approach is the same as yours. As soon as the algorithm sees a character from second string where the value for that char in the array is zero, the second string is not an anagram of first string and can return false immediately.
This way you only need to check the character values you actually use, and not all 127. It also generalizes trivially to larger character sets.