//********************************************************* v. 9/1/04
// Purpose:    Compare the values in two files.
//             Can by useful for software testing.
// Usage:      prog1 <file1> <file2>
//             numberic values are read, one at a time from each file.
//             these two values are compared.
//             Number of values read from each file, along with the
//             number of matches and mismatches are reported.
// Name:       M. Overstreet
//********************************************************************
// Listing contents:
//    Purpose
//    Usage
//    Pre & Postconditions
//    Reuse instructions
//    Compilation instructions
//    Known defects
//    Possible enhancements
//    Change history
//    Source code
//********************************************************************
// Precondtion:
//    2 files, each containing numeric values separated by white space.
//      files have only numeric contents.
// Postcondition:
//    A count of numeric matches and mismatches is produced
//********************************************************************
// Reuse instructions:  this is so short, it has limited reuse
//    potential, but the code may server as an example of
//    command line parameter passing and error handling.
//********************************************************************
// Compilation
// Under UNIX or Linux:
//    g++ -o prog1 -g prog1.cpp
//********************************************************************
// Known defects:
//   1.  doesn't produce required statistics.
//   2.  doesn't handle case where the two files have a different number
//       of values.  makes handling eof trickier.
//********************************************************************
// Possible enhancements
//    Floats should never by compared for exact matches; the program
//    should determine if numberics values are ints for floats,
//    then compare ints for exact matches, floats for precise
//    matches.
//********************************************************************
//  Change history:
//    None, it's a new example.
//********************************************************************

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

int main( int argc, char *argv[] )
{
   if(argc !=3)
   {
     cout << "Improper usage: prog1 <file1> <file2>" << endl;
     return 1;
   }

// Open and test file stream associated with first file
  ifstream file1( argv[1] );
  if ( !file1 ) 
  {
    cerr << argv[0] << ": " << argv[1] <<
      " not a valid file name" << endl;
    return 1;
  }

// Open and test file stream associated with second file
  ifstream file2( argv[2] );
  if ( !file2 ) 
  {
    cerr << argv[0] << ": " << argv[2] <<
      " not a valid file name" << endl;
    return 1;
  }

// Read data from each file until eof
  double val1, val2;
  int matchct = 0, mismatchct = 0;
  file1 >> val1;
  file2 >> val2;
  while ( file1 || file2 )
  {
    if ( val1 != val2 )
      {
      cout << "mismatch!" << endl;
      mismatchct++;
      }
    else
      matchct++;
    file1 >> val1;
    file2 >> val2;
  }

// Print run statistics
  cout << matchct << " matches" << endl;
  cout << mismatchct << " mismatches" << endl;

}