A small program

nmansour · 10-22-2007, 01:09 PM

Hi,

I am learning C++ and I was trying this code from the book I use:

Code:

#include <iostream>
using namespace std;
#include <conio.h>	//for getche()

int main()
    {
    int chcount=0;
    int wdcount=1;
    char ch= 'a';

    cout << "Enter a phrase: ";
    while( ch != '\r' )
       {
       ch = getche();
       if( ch == ' ')
       wdcount++;
       else
       chcount++;
       }
    cout << "\nWords= " << wdcount << endl
         << "\nLetters= " << (chcount -1) << endl;
    return 0;
    }

As you see, it uses the library conio.h. I know that this is a win32 library. I have tried to find it for Linux and I failed.

How would I adjust this code to run it on a Linux machine?

I have tried to install this library through a package called linux-conio-102 from here but I had the following problem here.

I use Fedora 7 on an AMD 64 Athlon Machine.

Any help would be greatly appreciated!

Noha

reverse · 10-22-2007, 01:17 PM

Just curious, what book are you using? (You should probably get a different one anyway)

nmansour · 10-22-2007, 01:21 PM

Umm,

I thought about changing the book, too. Bit I think it is a good book (just personal opinion)
The Book's name is "Waite Group's Object-Oriented Programming in C++, Third Edition" by "Rober Lafore".

If you have any other book suggestions, please let me know.

Noha

rstewart · 10-22-2007, 01:26 PM

Quote:

How would I adjust this code to run it on a Linux machine?

Code:

#include <iostream>
using namespace std;

int main()
{
    int chcount = 0;
    int wdcount = 0;
    int ch = 'a';

    cout << "Enter a phrase: ";
    while ( ch != '\n' )
    {
        ch = getchar()
        if ( ch == ' ' )
            wdcount++;
        else
            chcount++;
    }
    cout << "\nWords = " << wdcount << endl
         << "\nLetters = " (chcount - 1) << endl;
    return 0;
}

Works for me on my FC6 system.

nmansour · 10-22-2007, 01:45 PM

Small typos in your code:

Code:

#include <iostream>
using namespace std;

int main()
{
    int chcount = 0;
    int wdcount = 0;
    int ch = 'a';

    cout << "Enter a phrase: ";
    while ( ch != '\n' )
    {
        ch = getchar();
        if ( ch == ' ' )
            wdcount++;
        else
            chcount++;
    }
    cout << "\nWords = " << wdcount << endl
         << "\nLetters = " << (chcount - 1) << endl;
    return 0;
}

But of course thank you very much for the quick help. So it is the getchar() library then!?

Noha

PS.
Whenever M$ is involved, you will always have trouble.

nmansour · 10-22-2007, 02:24 PM

For this code to work and give correct results, I had to make a small change to the following line:

Code:

cout << "\nWords = " << wdcount << endl

to be

Code:

cout << "\nWords = " << (wdcount + 1) << endl

The code in its original form (the one I had from the book, do not need such a change, would someone explain?

Noha

PS.
I have tried

Code:

while (ch != '\r')

and the program compiled but after feeding in some words and spaces it does not respond after hitting the return key.

reverse · 10-22-2007, 03:50 PM

I was thinking of going for a book that is somewhat Linux (or portability*) tolerant.

rsashok · 10-22-2007, 04:49 PM

You should not use a kludge in you code without really understanding why (wdcount + 1) works instead of just (wdcount). I think that your word stream ends up with '\n', which leads to the last word not be counted. By the way, if you have few consecutive spaces between words your program also will give the wrong answer.

BTW: there is a Linux command 'wc' which does exactly what you trying to do, plus more.

nmansour · 10-22-2007, 05:26 PM

Hi,

reverse: Name some!

rsashok: thanks for the notices. the fact is that I am still learning, and as it may appear from this naive code, I am still getting my feet wet. I do know about teh multiple spaces problem (it is mentioned in the book) but thanks for the 'wc' command.

Noha

PAix · 10-22-2007, 08:21 PM

For the sake of completeness:

Code:

wc [option] filename

       -c, --bytes
              print the byte counts

       -m, --chars
              print the character counts

       -l, --lines
              print the newline counts

       -L, --max-line-length
              print the length of the longest line

       -w, --words
              print the word counts

I appreciate however that your object is learning and exercising your learning in C and not necessarily concerned that the functionality is available in the shell.
THE best book on the subject is:

Code:

The C Programming Language, 270 pages,
by Brian W. Kernighan and Dennis M.Richie, 2nd Edition, Published by Prentice Hall
ISBN 0-13-110362-8 (paperback)
ISBN 0-13-110370-9

C was originally designed for and implemented on the UNIX operating system on the DEC PDP-11, by Dennis Richie. It has an interesting history, as it was implemented on the UNIX operating system which it was subsequently used to re-write. Written by the people that defined the language. It really is recommended reading and has lots of exercises for us to do. If you are using this book and come across any problems, then you can at least cite the section of the book and almost all C programmers will be able to dust off their books and know what you are looking at. Very much a standard. A must in any C programmers library.

PAix

nmansour · 10-22-2007, 08:26 PM

PAix,

Thank you for your comment. I am learning C++ not C, though.
I do have the book you mentioned but almost simultaneously I decided to go for C++ not C as it is more likely the one I will use in my future studies.

Thanks again,

Noha

rstewart · 10-23-2007, 11:02 AM

Hi again,

Quote:

For this code to work and give correct results, I had to make a small change to the following line:

Code:

cout << "\nWords = " << wdcount << endl

Quote:

to be

Code:

cout << "\nWords = " << (wdcount + 1) << endl

Quote:

The code in its original form (the one I had from the book, do not need such a change, would someone explain?

Noha

PS.
I have tried

Code:

while (ch != '\r')

Quote:

and the program compiled but after feeding in some words and spaces it does not respond after hitting the return key.

Sorry for the delay in responding (and the typos), but I am at work and can only spend a few minutes at a time...

The difference between using the '\r', and the '\n' is one of the many differences between the way Linux and Windows handles end-of-line. Windows automatically adds the '\r' (cursor-return) character before the new-line character, Linux (UNIX) does not. This is why it is a good idea to run a source file through unix2dos, or dos2unix when transferring files between Linux and Windows. Those utilities take care of adding/stripping the cursor-return characters as well as an actual EOF character.

As far as making the change to increment wdcount before printing out the final stats, look at the algorithm. It is incrementing wdcount when it encounters a space character. Because the data line does not contain blank spaces after each word then the count will be off by one. Why it works under Windows I'm not really sure. You could run the code under Visual Studio's debug mode and take a look at the buffer being passed to your app, see if an extra blank character has been added or not.

And lastly, the getchar() function is part of the stdio (c runtime) library. Do a "man getchar" to see descriptions of it, and other supported functions.

I hope that this helps!

nmansour · 10-24-2007, 09:35 AM

rstewart:
Thanks for the reply, it really helped me a lot.

Noha,

Sorry for late reply, trouble with the net.