// File: strcmpEx.cpp
// Example of strcmp implemented with pointer arithmetic (no indexing)

#include <iostream>
#include <string.h>

using namespace std;

int strcmpPtr(char *str1,char *str2);

int main(int argc, char *argv[])
{ char s1[20],s2[20];
  if (argc>1) {		// Command line arguments present
    strcpy(s1,argv[1]);    
    strcpy(s2,argv[2]);
  }
  else {
    cout << "Compare two strings and see result\nEnter first string  >";
    cin >> s1;
    cout << "Enter 2nd string >";
    cin >> s2;
  }
  cout << "Our strcmp result is " << strcmpPtr(s1,s2) << endl;
  cout << "Result using strcmp is " << strcmp(s1,s2) << endl;  
}

int strcmpPtr(char *str1,char *str2)
{ for ( ;*str1 && *str2;str1++,str2++)
    if (*str1 != *str2)
      return(*str1-*str2);
  return(*str1-*str2);    
}