#include <stdio.h>
#include <string.h>

int main( void ){
  char *str1 = "hoge";

  printf("str1: '%s' (length: %ld by strlen)\n", str1, strlen(str1));
  printf("str1: '%s' (length: %d by StrLength)\n", str1, StrLength(str1));
}

int StrLength( const char *s ){
  int n = 0;
  while( *s++ != '\0' )
    n++;
  return n;
}