-:    0:Source:prog1example.cpp
        -:    0:Object:prog1example.bb
        -:    1://********************************************************* v. 9/1/04
        -:    2:// Purpose:    Compare the values in two files.
        -:    3://             Can by useful for software testing.
        -:    4:// Usage:      prog1 <file1> <file2>
        -:    5://             numberic values are read, one at a time from each file.
        -:    6://             these two values are compared.
        -:    7://             Number of values read from each file, along with the
        -:    8://             number of matches and mismatches are reported.
        -:    9:// Name:       M. Overstreet
        -:   10://********************************************************************
        -:   11:// Listing contents:
        -:   12://    Purpose
        -:   13://    Usage
        -:   14://    Pre & Postconditions
        -:   15://    Reuse instructions
        -:   16://    Compilation instructions
        -:   17://    Known defects
        -:   18://    Possible enhancements
        -:   19://    Change history
        -:   20://    Source code
        -:   21://********************************************************************
        -:   22:// Precondtion:
        -:   23://    2 files, each containing numeric values separated by white space.
        -:   24://      files have only numeric contents.
        -:   25:// Postcondition:
        -:   26://    A count of numeric matches and mismatches is produced
        -:   27://********************************************************************
        -:   28:// Reuse instructions:  this is so short, it has limited reuse
        -:   29://    potential, but the code may server as an example of
        -:   30://    command line parameter passing and error handling.
        -:   31://********************************************************************
        -:   32:// Compilation
        -:   33:// Under UNIX or Linux:
        -:   34://    g++ -o prog1 -g prog1.cpp
        -:   35://********************************************************************
        -:   36:// Known defects:
        -:   37://   1.  doesn't produce required statistics.
        -:   38://   2.  doesn't handle case where the two files have a different number
        -:   39://       of values.  makes handling eof trickier.
        -:   40://********************************************************************
        -:   41:// Possible enhancements
        -:   42://    Floats should never by compared for exact matches; the program
        -:   43://    should determine if numberics values are ints for floats,
        -:   44://    then compare ints for exact matches, floats for precise
        -:   45://    matches.
        -:   46://********************************************************************
        -:   47://  Change history:
        -:   48://    None, it's a new example.
        -:   49://********************************************************************
        -:   50:
        -:   51:#include <iostream>
        -:   52:#include <string>
        -:   53:#include <fstream>
        -:   54:using namespace std;
        -:   55:
        -:   56:int main( int argc, char *argv[] )
        1:   57:{
        1:   58:   if(argc !=3)
        -:   59:   {
    #####:   60:     cout << "Improper usage: prog1 <file1> <file2>" << endl;
    #####:   61:     return 1;
        -:   62:   }
        -:   63:
        -:   64:// Open and test file stream associated with first file
        1:   65:  ifstream file1( argv[1] );
        1:   66:  if ( !file1 ) 
        -:   67:  {
    #####:   68:    cerr << argv[0] << ": " << argv[1] <<
        -:   69:      " not a valid file name" << endl;
    #####:   70:    return 1;
        -:   71:  }
        -:   72:
        -:   73:// Open and test file stream associated with second file
        1:   74:  ifstream file2( argv[2] );
        1:   75:  if ( !file2 ) 
        -:   76:  {
    #####:   77:    cerr << argv[0] << ": " << argv[2] <<
        -:   78:      " not a valid file name" << endl;
    #####:   79:    return 1;
        -:   80:  }
        -:   81:
        -:   82:// Read data from each file until eof
        1:   83:  double val1, val2;
        1:   84:  int matchct = 0, mismatchct = 0;
        1:   85:  file1 >> val1;
        1:   86:  file2 >> val2;
        4:   87:  while ( file1 || file2 )
        -:   88:  {
        3:   89:    if ( val1 != val2 )
        -:   90:      {
        1:   91:      cout << "mismatch!" << endl;
        1:   92:      mismatchct++;
        -:   93:      }
        -:   94:    else
        2:   95:      matchct++;
        3:   96:    file1 >> val1;
        3:   97:    file2 >> val2;
        -:   98:  }
        -:   99:
        -:  100:// Print run statistics
        1:  101:  cout << matchct << " matches" << endl;
        1:  102:  cout << mismatchct << " mismatches" << endl;
        -:  103:
        1:  104:}