Please use C++

This first is required function, second is my function, can you help me to fix my function using bitwise and bit shifting operators?

bool all_uniqueletters (const string &s) { I TODO: returns true if al1 letters in string are unique, that is // no duplicates are found; false otherwise // You may use only a single int for storage and work with bitwise // and bitshifting operators // No credit will be given for other solutions