infinite loop

This is a discussion on infinite loop within the C Programming forums, part of the General Programming Boards category; I wrote this program to read a standard input file, eliminate all vowels and write the consonants to an output ...

  1. #1
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    infinite loop

    I wrote this program to read a standard input file,
    eliminate all vowels and write the consonants to an
    output file. My problem is once the input file is
    read the program keeps running only returning a
    "yyyyyy....etc" character (seems to be an infinite
    loop). How can I make this program end once the characters in the input file are read? Thanks.

    Code:
    #include <ctype.h>
    #include <stdio.h>
    
    int is_vowel(int c);
    
    int main(void)
    {
           int c;
           FILE *ifp, *ofp;
    
           ifp = fopen("textin.txt", "r");
           ofp = fopen("textout.txt", "w");
    
           while ((c = getc(ifp)) != 'EOF') 
           {
              if (!is_vowel(c)) 
                {
                     putc(c, ofp);
                }
           }
      return 0;
    }
    
    int is_vowel(int c)
    {
      c = toupper(c);
    
    return c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U';
    }

  2. #2
    ZuK
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    Code:
           while ((c = getc(ifp)) != EOF)
    Works fine. You should listen to compiler-warnings.
    Kurt

  3. #3
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    Thanks for the help. I guess that I never really paid attention to the warnings. As long as I got "Linking, bulid succeeded" I guess I thought I was good. Just begining to understand the concepts.

  4. #4
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    Quote Originally Posted by scudshouse
    Thanks for the help. I guess that I never really paid attention to the warnings. As long as I got "Linking, bulid succeeded" I guess I thought I was good. Just begining to understand the concepts.
    A basic rule is that, if a compiler complains it is because it (or, more accurately, the compiler writer) considers you have done something suspicious.

    Blindly ignoring warnings is a good way to get in trouble. Ignoring warnings is really only OK if you know what the warnings mean and are sure they do not indicate some real problem with your code.

    OTOH, running code through several compilers, and ensuring the code compiles cleanly (without error or warning) is quite helpful in creating code that is truly portable. Particularly if you tweak all of the compilers to ensure they complain about everything possible.

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