How To Think Like a Computer Scientist C++ Edition The Pretext Interactive Version

If we are looking for a letter in a string, we may not want to start at the beginning of the string. One way to generalize the find function is to write a version that takes an additional parameter—the index where we should start looking. Here is an implementation of this function.

size_t find(string s, char c, size_t i) {
  while (i < s.length()) {
    if (s[i] == c)
      return i;
    i = i + 1;
  }
  return string::npos;
}

Instead of invoking this function on an string, like the first version of find, we have to pass the string as the first argument. The other arguments are the character we are looking for and the index where we should start.

int main() {
  string quote = "The way to get started is to quit talking and begin doing.";
  cout << find(quote, 't', 11) << ", " << find(quote, 't', 42) << ", " << quote.find('t');
}