rounding up

This is a discussion on rounding up within the C++ Programming forums, part of the General Programming Boards category; i just started taking cpp classes in school and i got a new assignment. in this assignment i have to ...

  1. #1
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    rounding up

    i just started taking cpp classes in school and i got a new assignment. in this assignment i have to calculate how much it will cost for a customers carpet(after all the input).I also must use one function in this program. so i was wondering if there was a way i could make a function round up to the next number (ie if n=1.11 round it to n=2 or something). plz include examples.

    thanks

  2. #2
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    im still pretty new to C++ myself, and usually helping others is no place for someone with my knowlege level, but still....

    why not just make it simple. such as:

    //...

    a = x / y;
    /////////////
    b = x % y;
    if ( b > 0 )
    a = ++a;
    /////////////
    printf("%d", a);

    thats assuming that 'a' is an int, and when you divide x by y, it rounds down for a

    i dont know if that helped even in the slightest, but i figured i would try to do my part.

  3. #3
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    Printf can round up for you

    Code:
    #include <stdio.h>
    
    int main(void)
    {
    	float b = 1.90;
    	printf("%.0f",b);  // %.0f means no decimal places.
    	return 0;
    }

  4. #4
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    thanks for the quick replies!
    But i was wondering if i could mak eit round up all the time.

    (1.10=2 and 1.7=2)

  5. #5
    Confused Magos's Avatar
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    (int) rounds down all the time (truncates), so this should always round up:

    float Var;
    int AnotherVar=(int)Var+1;
    MagosX.com

    Give a man a fish and you feed him for a day.
    Teach a man to fish and you feed him for a lifetime.

  6. #6
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    use ceil(...) to round up

    no offense to the fine examples but .....
    According to the MSDN help files... use them and you rely on this board much less...

    /* FLOOR.C: This example displays the largest integers
    * less than or equal to the floating-point values 2.8
    * and -2.8. It then shows the smallest integers greater
    * than or equal to 2.8 and -2.8.
    */

    #include <math.h>
    #include <stdio.h>

    void main( void )
    {
    double y;

    y = floor( 2.8 );
    printf( "The floor of 2.8 is %f\n", y );
    y = floor( -2.8 );
    printf( "The floor of -2.8 is %f\n", y );

    y = ceil( 2.8 );
    printf( "The ceil of 2.8 is %f\n", y );
    y = ceil( -2.8 );
    printf( "The ceil of -2.8 is %f\n", y );
    }
    zMan

  7. #7
    Registered User Dual-Catfish's Avatar
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    You might also want to check
    if (floor(var) == var) before you go typecasting int on your float.
    Take the following example

    floar var;
    cin >> var;
    cout >> (int)var+1;

    If the user enters an integer number, casting int on it and adding 1 won't give you a desired result, as it would already be an int.

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