Thread: File scan not working

  1. #1
    Registered User
    Join Date
    Jan 2008
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    182

    File scan not working

    I want this program to scan a text file (given as an argument) and just put the alpha characters it finds. Why isn't it working? Thanks!

    Code:
    #include <stdio.h>
    #include <ctype.h>
    
    int main(int argc, char *argv[])
    {
        int ch;
        FILE *input = NULL;
        
        if(!(input = fopen(argv[1], "r"))) {
            printf("Error opening file!\n");
            return 1;
        }
        
        while(ch = fgetc(input) != EOF) {
            if(isalpha(ch))
                putchar(ch);
        }
        
        return 0;
    }
    Last edited by samus250; 09-27-2008 at 12:49 PM.

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
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    The edge of the known universe
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    39,660
    You've written this
    while(ch = (fgetc(input) != EOF))

    You want this
    while((ch = fgetc(input)) != EOF)

    Note the use of ( )
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    Registered User
    Join Date
    Jan 2008
    Posts
    182
    It works now. Thanks!

  4. #4
    Registered User ssharish2005's Avatar
    Join Date
    Sep 2005
    Location
    Cambridge, UK
    Posts
    1,732
    Well that program works fine to me!! may be place a getchar before the return 0.

    EDIT: Perhaps, I did place the brakets when i tested that code. But dint mentioned it here lol. YES you need to brakets!

    ssharish

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