Simple hex to ascii char conversion

This is a discussion on Simple hex to ascii char conversion within the C Programming forums, part of the General Programming Boards category; Hello, I've written a program that takes a file of hex values, and converts it into characters. I'll end up ...

  1. #1
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    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;
    }

  2. #2
    Programming Wraith GReaper's Avatar
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    scanf RETURNS EOF, it never sets any of its arguments to NULL. There's a difference.
    Devoted my life to programming...

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    Quote Originally Posted by GReaper View Post
    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?

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    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

  5. #5
    TEIAM - problem solved
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    Why are you not using argc/argv[] and the fopen functions?

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    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.

  7. #7
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    Also keep in mind:
    - "getchar()" returns an integer value
    - EOF is an integer, not a character

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