files > 65535 bytes wont read in dos

Hello, I hope you can welcome one more newbie into the ranks!

For practice I've been trying to make a program (16bit dos) that reads each byte in a file. I've set up an array of 256 elements...array[256] and each time that byte comes up I add one to the corresponding element in the array. Like I said its just for practice.

My real problem comes when I try to read files that are larger than 65535 bytes. The program (stops reading???) or something once it gets past this point.

Is this a limitation of 16bit mode (would make sense) and was wondering if there is something I'm missing. Here's the functions I use.

FILE *filein

fopen("c:/something.txt","rt");

input=fgetc(filein);

fclose(filein);

Thats the file functions I use and the rest is just simple stuff.

Thanks for the help!

You'd better post the whole program.

You certainly can't read a large file in one single call, but there should be no problem reading the file one character at a time.

Code:

---


#include <stdio.h>

void main()
{

        FILE *filein;
        int array[256]={0};
        int input=0;
        bool done=false;

        filein=fopen("c:/something.zip","r");

        while (!done)
        {
                input=fgetc(filein);
               
                if (input!=EOF)
                {
                        array[input]++;
                }
                else
                {
                        done=true;
                }

        }

        fclose(filein);

        //program goes on to diplay how many hits on each number

        return;
       
}

---

Works good for the first 65KB...

I'm using Win98 and MVCS 6.0

> void main()
main returns an int - see the FAQ
Successful programs end with
return 0;

> bool done=false;
bool is a C++ type

Rename your prog.cpp to be prog.c, to make sure you're using 'C' language and not C++ (which is the MSVC default)

> filein=fopen("c:/something.zip","r");
Use "rb" for binary files - your original post suggested you were reading a text file
You should also add

Code:

---

if ( filein == NULL ) {
    perror( "Unable to open file" );
    return 1;
}

---

Thank you Salem.

using "rb" was the trick in the fopen funtion.