最終答案球體積的容量無效

Question

我創建了這個程序，應該基本上使用公式V = Pi * h^2（3r-h）/ 3，但是我的最終答案沒有加起來。

例如：如果我用1代替半徑和2代表高度，我應該得到4.18，但是通過程序我得到-1。

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

double calculatevolume(double); 

double main() { 
    double radius, height; 
    double sum; //for storing the radius of the reservoir given by the user 
    //for storing the calculated volume of the water. 

    printf("Please enter the Radius in meters first and then the Height in meters right after:\n"); //Displays the message on the screen 

    scanf("%lf",&radius); 
    printf("Value of r: %f\n", radius); 

    scanf("%lf",&height); 
    printf("Value of h: %f\n", height); 

    sum = calculatevolume(sum); 

    printf("For a reservoir of radius: %.2f m\nAnd a water depth: %.2f m\nThe water volume is: %.2f m^3\n",radius,height,sum); 

    system("PAUSE"); 
} 

double calculatevolume(double sum) { 
    double radius; 
    double height; 

    sum = ((((3 * radius) - height)/3) * 3.14 * height * height); 

    return sum; 
} 

Answer 1

試試這個代碼，你應該通過高度和半徑的功能：

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

double calculatevolume(double,double,double); 
double main() { 
    double radius, height; 
    double sum; //for storing the radius of the reservoir given by the user 
    //for storing the calculated volume of the water. 

    printf("Please enter the Radius in meters first and then the Height in meters right after:\n"); //Displays the message on the screen 

    scanf("%lf", &radius); 
    printf("Value of r: %f\n", radius); 


    scanf("%lf", &height); 
    printf("Value of h: %f\n", , height); 

    sum = calculatevolume(sum,radius,height); 

    printf("For a reservoir of radius: %.2f m\nAnd a water depth: %.2f m\nThe water volume is: %.2f m^3\n",radius,height,sum); 

    system("PAUSE"); 
} 

double calculatevolume(double sum, double radius, double height) { 
    sum = ((((3 * radius) - height)/3) * 3.14 * height * height); 
    return sum; 
} 

您也可以從函數頭刪除總和，它沒有必要將它傳遞