Thread: Simple hex to ascii char conversion

Hello, I've written a program that takes a file of hex values, and converts it into characters. I'll end up using(running linux)./byte2char < hexvalues.txt > newvalues.txt to do the conversion. The thing is, it works perfectly, it's just the loop won't end. I run it, and I have to stop it manually with ctrl+c. After only about half a second of running, I'll end up with the converted text and then about 2 million extra lines of nothing. Any help please?

Thanks

Code:

#include<stdio.h>

int main()
{
    char c;
    char x;


    while (c!= EOF)
        {
        scanf("%x",&c);

        printf("%c",c);
        }

    return 0;
}

Originally Posted by GReaper

scanf RETURNS EOF, it never sets any of its arguments to NULL. There's a difference.

I'm not quite sure what you mean. Would you elaborate a little please?

There are several things wrong with your program. First your format specifier in your scanf() call is for an unsigned int not a char. Second I recommend you use getchar() instead of scanf() if you want a value you will be able to compare against EOF.

Jim

Why are you not using argc/argv[] and the fopen functions?

Thank you jim. I got it to work. At first I tried using just getchar, but it didn't work because getchar grabs letter by letter, and I need to grab them by pairs, because they're hex values separated by spaces. But then with with scanf it ran into trouble too. Apparently if you use c=getchar(), and then scanf after that, it works just fine.

Also keep in mind:
- "getchar()" returns an integer value
- EOF is an integer, not a character