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


int main()
{
    ifstream myfile;
    string filename;
    string a;
    int b=1;
    
    
    cout << "Please enter filename: ";
    cin >> filename;
    
    myfile.open(filename.c_str());


    
    if (!myfile.good())
    {
        cout << "File cannot be found" << endl;
        system("pause");
        
        b++;
    }


    
    if (b<1)
    {
    cout << "Please enter filename again: ";
    system ("pause");
    cin >> filename;
  
    
    myfile.open(filename.c_str());
    return 0;
    }



    while(!myfile.eof())
    {
        // use getline to read entire line  
        getline(myfile, a);
        
        cout << a << endl;
    }
    
    myfile.close();    
    system("pause");
    return 0;
}

do
{
    cout << "Please enter filename: ";
    cin >> filename;    
    myfile.open(filename.c_str());    
    if (!myfile.good())
    {
        cout << "File cannot be found" << endl;
    }        
}while(!myfile.good());

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


int main()
{
    ifstream myfile;
    string filename;
    string a;
    


do
{
    cout << "Please enter filename: ";
    cin >> filename;    
    myfile.open(filename.c_str());    
    if (!myfile.good())
    {
        cout << "File cannot be found" << endl;
    }        
}while(!myfile.good());
    


    while(!myfile.eof())
    {
        // use getline to read entire line  
        getline(myfile, a);
        
        cout << a << endl;
    }
    
    myfile.close();    
    system("pause");
    return 0;
}
    

/*
    Demo of converting DECIMAL NUMERALS to ROMAN NUMERALS ...
    Modified for strings, and to use the MSD, (Most Significant Digit)
    rather than the LSD (Least Significant Digit) method used by Randy.
    Randall Hyde is the author of HLA (High Level Assembly) ... See ...
    http://webster.cs.ucr.edu/AoA/index.html
    http://developers-heaven.net/forum/index.php/topic,46.0.html
*/
#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>

#define debugging true

using namespace std;

string convert( int n )
{
    if( n > 3999 ) return "Largest number handled is 3999";
    if( n < 1 ) return "Smallest number handled is 1";
    
    string romanNum[] =
    { "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX" };
    char buffer[20];
    itoa( n, buffer, 10 ); // convert integer to C string char's
    string nStr = string(buffer); // convert C string to C++ string
    string rm =""; // to hold the Roman Number
    int msd;
    for( int i=0; i<nStr.length(); ++i )
    {
        // Extract the NEXT Most Significant Digit (MSD)
        //  from the number 'n' ... as a string now, i.e. 'nStr'

        //  msd =  ???? ...................................
        
        // Here is the trick, (from Randy of HLA), that makes this work ...
        // 'Multiply' the Roman Number by Ten.  This is achieved by
        // swapping the characters in the char string 's1' below
        // with their corresponding character in char string 's2' below ...
        char s1[] = "IVXLCDM";
        char s2[] = "XLCDM**";
        int j, k;
        for( j=0; j< rm.length(); j++ )
        {
            for( k=0; k<7; k++ )
            {
                if( rm[j] == s1[k] )
                {
                    rm[j] = s2[k];
                    break;
                }
            }
        }
        // Convert the current MSD to a string
        // and append to the end of "rm".
        rm = rm + romanNum[msd];
    }
   return rm;      
}

void convertAndShow( int n )
{
    cout << "The number " << n << " converted is " << convert(n) << endl;
}

int main()
{
    // get file name and open that file to read numbers
    // and validate that it was opened ok ...
    ifstream myfile;
    string filename;
    
// or for testing via keyboard input ...
#if debugging
    goto testing;
#endif

    do
    {
        cout << "Please enter filename: ";
        myfile.clear();
        cin >> filename;
        cin.sync(); //eat any char's that cin may have missed in in-stream  
        myfile.open( filename.c_str() );    
        if( myfile.fail() )
            cout << "File cannot be found" << endl;    
    }while( myfile.fail() );

    int a;
    while( myfile >> a )
        convertAndShow( a );
        
    myfile.close();

#if debugging  
    testing:
    string message = "Enter number from the keyboard (q to quit) : ";
    cout << message;
    while( cin >> a ) { convertAndShow( a ); cout << message; }
    cin.clear();
    cin.sync();
#endif

    cout << "\nPress 'Enter' to continue ... ";
    cin.get();
}

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <cctype>

using namespace std;


int main()
{
     ifstream myfile;
     string filename;
     string a;
     char romanType;
     int convert;
  
    

    do
    {
      cout << "Please enter filename: ";
      cin >> filename;    
      myfile.open(filename.c_str());    
      if (!myfile.good())
     {
        cout << "File cannot be found" << endl;
     }        
    }while(!myfile.good());
    

    while (!myfile.eof())
    {
     getline(myfile,a);
     for(int i=0; i<a.length(); i++)
     a[i] = toupper (a[i]);    
/*     for(int i=0; i<a.length(); i++)
    {
     if (!isdigit (a[i]))
  
     cout << a << " invalid " << endl;
        
    else
    {
         cout << a << endl;
    }
    }
*/  
    
     }
     int M, D, C, L, X, V, I, IV, IX, XL, XC, CD, CM;
     char roman;
     romanType::romanType(char &ch)
     {
      M = 1000;
      D = 500;
      C = 100;
      L = 50;
      X = 10;
      V = 5;
      I = 1;
      IV = 4;
      IX = 9;
      XL = 40;
      XC = 90;
      CD = 400;
      CM = 900;

      
      cout << ch << endl;
      
      roman=ch;    
      
      }
       int romanType::convert{
    if (roman == 'M'){
        return 1000;                  
    }else if(roman == 'D'){
        return  500;
    }else if(roman == 'C'){
        return  100;
    }else if(roman == 'L'){
        return  50;
    }else if(roman == 'X'){
        return  10;
    }else if(roman == 'V'){
        return  5;
    }else if(roman == 'I'){
        return  1;
    }else if(roman == 'IV'){
        return  4;
    }else if(roman == 'IX'){
        return  9;
    }else if(roman == 'XL'){
        return  40;
    }else if(roman == 'XC'){
        return  90;
    }else if(roman == 'CD'){
        return  400;
    }else if(roman == 'CM'){
        return  900;
    }
    return 0;  
}
    

    
    myfile.close();    
    system("pause");
    return 0;
}