Given a string s and a string t, return a string in which all the characters of s that occur in t have been replaced by a _ sign. The comparisons are case sensitive.

Complete the following file:


#include <iostream> #include <string> using namespace std; /** Returns the index of the first occurrence of t in s, or -1 if t doesn't occur in s. */ int find(string s, string t) { for (int i = 0; i + t.length() < s.length(); i++) { if (s.substr(i, t.length()) == t) { return i; } } return -1; } string replaceCharactersWithUnderscores(string s, string t) {