isdigit()

This is a discussion on isdigit() within the C Programming forums, part of the General Programming Boards category; When I run this program: Code: #include <stdio.h> #include <ctype.h> int main(void) { int c = 0; printf("Enter a digit ...

  1. #1
    ... kermit's Avatar
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    isdigit()

    When I run this program:
    Code:
    #include <stdio.h>
    #include <ctype.h>
    
    int main(void)
    {
      int c = 0;
      printf("Enter a digit between 0 - 9\n");
      fflush(stdout);
      c = getchar();
      printf("The value from isdigit: %d\n", isdigit(c));
      return 0;
    }
    I expect the output to be 'The value from isdigit: 0' for any non digit, and 'The value of isdigit: 1' for any digit. When it is a non digit entry I get 0 as I expected, but for a digit entry, I get 2048. Why is this so?

  2. #2
    & the hat of GPL slaying Thantos's Avatar
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    The values returned are nonzero if the character c falls
    into the tested class, and a zero value if not.

  3. #3
    ... kermit's Avatar
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    Ah, I thought this was the case, but I wanted to be sure. Thanks Thantos

    ~/

  4. #4
    Registered User linuxdude's Avatar
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    you don't need the fflush(stdout); because you have the \n in the printf string, which automatically flushes the buffer right?(C Gurus correct me if I am wrong)

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