c - 打印解决方案(C 语言新手)

Question

我不明白为什么我的程序不会打印最终的解决方案(totalDough)。输入为 8,10,12，然后是 40,100 和 200:

const int DOUGH_PER_SQFT = 0.75;
const int INCHES_PER_FEET = 12;
#define M_PI 3.14159265358979323846

int main(){

    // Declare and initialize variables

    int smallRIn;
    printf("What is the radius of your small pizza, in inches?\n");
    scanf("%d", &smallRIn);
    int mediumRIn;
    printf("What is the radius of your medium pizza, in inches?\n");
    scanf("%d", &mediumRIn);
    int largeRIn;
    printf("What is the radius of your large pizza, in inches?\n");
    scanf("%d", &largeRIn);


    // Get number of pizzas sold
    int smallSold;
    printf("How many small pizzas do you expect to sell this week?\n");
    scanf("%d", &smallSold);
    int mediumSold;
    printf("How many medium pizzas do you expect to sell this week?\n");
    scanf("%d", &mediumSold);
    int largeSold;
    printf("How many large pizzas do you expect to sell this week?\n");
    scanf("%d", &largeSold);

    // Convert radii to feet

    double smallRFeet, mediumRFeet, largeRFeet;
    smallRFeet = smallRIn/INCHES_PER_FEET;
    mediumRFeet = mediumRIn/INCHES_PER_FEET;
    largeRFeet = largeRIn/INCHES_PER_FEET;

    // Calculate top surface areas of each type of pizza.

    double areaSmall, areaMedium, areaLarge;
    areaSmall = smallSold*M_PI*pow(smallRFeet,2);
    areaMedium = mediumSold*M_PI*pow(mediumRFeet,2);
    areaLarge = largeSold*M_PI*pow(largeRFeet,2);

    // Print solution
    double dough;
    dough = areaSmall+areaMedium+areaLarge;
    double total_dough;
    total_dough = dough * DOUGH_PER_SQFT;

    printf("The total amount of dough you need to order this week is", total_dough);

    return 0;
}

我做错了什么？

Answer 1

const int DOUGH_PER_SQFT = 0.75;

这是一个 int 值，而 int 不是 float ，因此这会转换为:

0

这基本上意味着在你的最终方程中

total_dough = dough * DOUGH_PER_SQFT;

它将计算为 0，因为每平方英尺的面团等于 0。

这可以通过更改来纠正:

const int DOUGH_PER_SGFT = 0.75

进入:

const double DOUGH_PER_SGFT = 0.75