/** @file list5904.cpp */
/** Listing 59-4. Using Pointer Arithmetic to Determine the Length of a C String */
#include <cstring>

std::size_t my_std_strlen(char const* str)
{
   char const* start(str);      // remember the start of the string
   while (*str != 0)            // while not at the end of the string
      ++str;                    // advance to the next character
   return str - start;          // compute string length by subtracting pointers
}