check if string A is a sub sequence of string B

subsequence.cc

/*
 * Credits: http://stackoverflow.com/questions/8599374/sub-sequence-occurrence-in-a-string
 */

bool checkSubSequence(string A, string B) {
  int pos = -1;
  bool ok = true;
  
  for (int i=0; i!=A.size() && ok; i++)
    ok = (pos = B.find(A[i], pos+1)) != string::npos;
    
  return ok;
}