atof() acting weird?

This is a discussion on atof() acting weird? within the C Programming forums, part of the General Programming Boards category; This is how the program is setup. The atof() function isn't working the way it should, and is producing bogus ...

  1. #1
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    atof() acting weird?

    This is how the program is setup.

    The atof() function isn't working the way it should, and is producing bogus numbers. Any idea's?

    Normally I'd just start with a float, but this is for a bigger program. I just made a little script that re-produces this problem for me. Any idea's?


    Code:
    #include <stdio.h>
    
    int main(void)
    {
        char test[100];
        double num = 0;
    
    
        printf("Testing number: ");
        gets(test);
        
        num = atof(test);
        printf("num = %.2f\n", num);
    
        return 0;
    }
    Results:

    Testing number: 45
    num = 2293232.00

    Thanks,
    Mellowz
    Last edited by Mellowz; 07-07-2006 at 08:08 PM.

  2. #2
    Code Goddess Prelude's Avatar
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    Perhaps you should include stdlib.h.
    My best code is written with the delete key.

  3. #3
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    Noob question...What atof() function was the program using since the header wasn't included, or why didn't the compiler complain?


    And gets() ftw
    Last edited by Link_26; 07-07-2006 at 08:38 PM.

  4. #4
    Code Goddess Prelude's Avatar
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    9,796
    >What atof() function was the program using since the header wasn't included
    Undefined behavior.

    >or why didn't the compiler complain?
    It probably didn't have warnings set high enough.

    >And gets() ftw
    My best code is written with the delete key.

  5. #5
    Registered User
    Join Date
    Mar 2006
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    Don't use gets. It's too safe. Use fgets. It's more dangerous. Why
    Code:
    #include <stdio.h>
    
    void J(char*a){int f,i=0,c='1';for(;a[i]!='0';++i)if(i==81){
    puts(a);return;}for(;c<='9';++c){for(f=0;f<9;++f)if(a[i-i%27+i%9
    /3*3+f/3*9+f%3]==c||a[i%9+f*9]==c||a[i-i%9+f]==c)goto e;a[i]=c;J(a);a[i]
    ='0';e:;}}int main(int c,char**v){int t=0;if(c>1){for(;v[1][
    t];++t);if(t==81){J(v[1]);return 0;}}puts("sudoku [0-9]{81}");return 1;}

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