Help With Calculation

This is written in C. The program works, but the calculation is wrong, can someone tell me what I am doing wrong?

Thank You

Code:

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#include "stdafx.h"
#include <math.h>

#using <mscorlib.dll>

using namespace System;

// Function prorotypes

 void sphere_volume (double);

// PI is a constant

const double PI=3.14159;


int _tmain()


{
        // Integer local to Main to store initial radius value
double r;

        printf("Please Enter A Positive Radius Value\n");
        scanf("%lf", &r);

// If Else Function To Make Sure The User Types A Positive and Not A Negative Integer.

        if (r >= 0)
                sphere_volume (r);

        else
                printf("You Must Enter A Positive Integer!!!! Not A Negative Integer!!!\n");

        return 0;

}

// This Is The Fnction That Does The Calculations For The Volume.

void sphere_volume (double radius)

{
        double  radius_cubed;

        double exponent=3;

        double volume;

        printf("This Is The Test To See If R Was Passed To The Function: %lf\n", radius);

        radius_cubed=pow(radius, exponent);

        volume=(4/3)*PI*radius_cubed;

        printf("The Volume Of The Sphere is %lf\n", volume);
}

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There is a C programming forum for C programs.

Your problem is this:

Code:

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(4/3)

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make it

Code:

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(4.0/3)

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The reason is: 4/3 is integer division. The fractional part is discarded. So it ends up being 1, not 1.33333333333333. 4.0 is a floating point number, and the result of that expression is the expected value, 1.3333333333333333.

Oh yes, and

Code:

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printf("The Volume Of The Sphere is %lf\n", volume);

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Should be

Code:

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printf("The Volume Of The Sphere is %f\n", volume);

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With printf(), %lf doesn't exist.

Thank you, I am trying it now. Were is the C programming forum for C programs.

Sorry I found it.

Thank You