need to convert double to number with 1 digit after the floating point

This is a discussion on need to convert double to number with 1 digit after the floating point within the C Programming forums, part of the General Programming Boards category; I'm getting double as a result of a function. now I have to convert it to be a number with ...

  1. #1
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    need to convert double to number with 1 digit after the floating point

    I'm getting double as a result of a function.

    now I have to convert it to be a number with only one digit after the floating point, how can I do it?

    is there a math function that can help me?

    thanx

  2. #2
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    only one Digit after the floating point

    double d = 1234.567;
    printf( "%.1f\n", d );


    the printf only shows the number as if it was with one digit after the floating point.

    BUT, I need to save it as a new double/float or even override the double I get from the function, this new variable should have only one digit after the floating point - all the other digits must be zero!!!

    I'm using it for a rotation function in OpenGL

  3. #3
    End Of Line Hammer's Avatar
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    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

  4. #4
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    Can I get the number I'm looking for?

    I looked at http://www.eskimo.com/~scs/C-faq/q14.1.html
    and it is about the printing method again.

    are you trying to tell me that there is no way I can get a number with only one digit after the floating point?

  5. #5
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    It's pure maths:

    Code:
    #include <stdio.h>
    #include <math.h>
    
    int main()
    {
    	double a = 5.123456, b;
    
    	b = floor( a * 10 ) / 10;
    
    	printf( "%lf\n", b );
    	return 0;
    }

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