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doubles don't work!!!!!!!

This is a discussion on doubles don't work!!!!!!! within the Windows Programming forums, part of the Platform Specific Boards category; I downloaded both the newest (12.I forget) and 10.05 versions of codeblocks on my windows 7 64bit laptop. Whenever I ...

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    doubles don't work!!!!!!!

    I downloaded both the newest (12.I forget) and 10.05 versions of codeblocks on my windows 7 64bit laptop. Whenever I try and do any sort of operation with a double type variable (print, scan, any sort of math), even if it is initialized to something, the result always comes up as 0.00000000. Anyone got any ideas?

    for example

    double i = 9.4;
    printf ("%lf", i);

    prints 0.0000000

  2. #2
    - - - - - - - - oogabooga's Avatar
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    Don't use %lf with printf. Just use %f for both float and double.
    scanf needs %lf for a double, though.
    The cost of software maintenance increases with the square of the programmer's creativity. - Robert D. Bliss

  3. #3
    11DE784A SirPrattlepod's Avatar
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    Quote Originally Posted by oogabooga View Post
    Don't use %lf with printf. Just use %f for both float and double.
    scanf needs %lf for a double, though.
    That's correct. It really shouldn't matter though.

    OP, please submit a complete snippet that is compilable and exhibits the problem you're observing.

    E.g.

    Code:
    #include <stdio.h>
    
    int main(void)
    {
        double i = 9.4;
        printf ("%lf", i);
        return 0;
    }

  4. #4
    - - - - - - - - oogabooga's Avatar
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    You're right of course that it shouldn't matter, but sadly it does on gcc 4.7.1, at least.
    The ell should just be ignored, but instead it gets weird.
    E.g., your code snippet just prints 0.00000000.
    I guess it's a bug.
    EDIT: Just did a quick test. Apparently gcc (4.7.1, at least) interprets a small ell as a capital ell, i.e., if you make i a long double, it prints correctly.
    Last edited by oogabooga; 10-30-2013 at 01:27 AM.
    SirPrattlepod likes this.
    The cost of software maintenance increases with the square of the programmer's creativity. - Robert D. Bliss

  5. #5
    11DE784A SirPrattlepod's Avatar
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    Quote Originally Posted by oogabooga View Post
    You're right of course that it shouldn't matter, but sadly it does on gcc 4.7.1, at least.
    The ell should just be ignored, but instead it gets weird.
    E.g., your code snippet just prints 0.00000000.
    I guess it's a bug.
    EDIT: Just did a quick test. Apparently gcc (4.7.1, at least) interprets a small ell as a capital ell, i.e., if you make i a long double, it prints correctly.
    Weird. It's not undefined behaviour... it's defined as having no effect

    .... has no effect on a following a, A, e, E, f, F, g, or G conversion specifiers.
    Must be gcc bug.

    For the snippet I provided, gcc 4.8.2 prints 9.400000

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    I tried all the changes you guys suggested but still no luck. I was wondering, is it possible that my anti-virus might have stopped a part of codeblocks from downloading? I scrolled through the logs and it didn't mention anything. Also I would expect an error from codeblocks if it was missing some of its self.

  7. #7
    - - - - - - - - oogabooga's Avatar
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    No, that's not possible. You're just doing something wrong. Try this:
    Code:
    #include <stdio.h>
     
    int main(void)
    {
        double d = 9.4;
        printf ("%f\n", d);
        return 0;
    }
    The cost of software maintenance increases with the square of the programmer's creativity. - Robert D. Bliss

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