Programming Tips - How do I convert a STL vector iterator into an integer index?

Date: 2008apr18 Language: C++ Keywords: stl, std Q. How do I convert a STL vector iterator into an integer index? A. Do this:
#include <vector> typedef std::vector<char *> MYARRAY; // This does the trick inline const int iterator_to_index(MYARRAY &a, MYARRAY::iterator it) { return it - a.begin(); } // Example use main() { MYARRAY a; int index; a.push_back("one"); a.push_back("two"); a.push_back("three"); for (MYARRAY::iterator it = a.begin(); it != a.end(); it++) { index = iterator_to_index(a, it); printf("index=%d\n", index); } }