调用函数并结束循环

问题描述

我一直在调用 getgallons 函数。我试图返回 gallons、acrearea 和 sNowdepth，但结果总是以 0 结尾。我还想以“输入雪的深度（英寸）”来结束循环已下降（或 -1 退出）：" 没有 break。

#include <iostream>
using namespace std;

double getgallons(float sNowdepth);

int main()
{
    float sNowdepth,acrearea;
    double gallons;
    
    cout << "Enter the depth (inches) of sNow that has fallen (or -1 to exit): ";
    cin >> sNowdepth;
    cout << "Enter the area (acres) that the sNow covers: ";
    cin >> acrearea;
    cout << "This amount of sNow equals " << gallons << " gallons of water." << endl << endl;
    
    
    
    while (sNowdepth > 0)
    {
        cout << "Enter the depth (inches) of sNow that has fallen (or -1 to exit): ";
        cin >> sNowdepth;
        cout << "Enter the area (acres) that the sNow covers: ";
        cin >> acrearea;
        cout << "This amount of sNow equals " << gallons << " gallons of water." << endl << endl;
    }    
    
    cout << "Enjoy the sNow!" << endl;
    cout << "Press any key to continue...." << endl;
    
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(1);
    
    gallons = getgallons(sNowdepth);

    return 0;
}

double getgallons(float sNowdepth)
{
    float acrearea;
    double gallons;
    const int WATER_galLONS = 27154;
    gallons = sNowdepth * acrearea * WATER_galLONS;
    
    return gallons;
}

解决方法

这就是你想要的。

#include <iostream>
using namespace std;

double getGallons(float snowdepth,float acrearea);

int main()
{
    while (true)
    {
        float snowdepth,acrearea;

        cout << "Enter the depth (inches) of snow that has fallen (or -1 to exit): ";
        cin >> snowdepth;
        if( snowdepth < 0 )
            break;

        cout << "Enter the area (acres) that the snow covers: ";
        cin >> acrearea;

        double gallons = getGallons(snowdepth,acrearea);

        cout.setf(ios::fixed);
        cout.setf(ios::showpoint);
        cout.precision(1);

        cout << "This amount of snow equals " << gallons << " gallons of water.\n\n";
    }    

    cout << "Enjoy the snow!" << endl;

    return 0;
}

double getGallons(float snowdepth,float acrearea)
{
    const int WATER_GALLONS = 27154;
    return snowdepth * acrearea * WATER_GALLONS;
}

,

您忽略了用户对 acrearea 的输入，使用不相关且未初始化的 acrearea 来计算加仑数。

此外，您根本没有为每组用户输入计算 gallons。您仅在用户选择结束循环后计算 gallons。

就此而言，您为用户提供了在第一次输入时退出的选项，但您没有尊重用户是否真的选择在第一次输入时退出。

尝试更像这样的事情：

#include <iostream>
#include <iomanip>
#include <limits>
using namespace std;

double getGallons(float snowdepth,float acrearea);

int main()
{
    float snowdepth,acrearea;
    double gallons;

    do {
        cout << "Enter the depth (inches) of snow that has fallen (or -1 to exit): ";
        cin >> snowdepth;
        if (snowdepth > 0) {
            cout << "Enter the area (acres) that the snow covers: ";
            cin >> acrearea;

            gallons = getGallons(snowdepth,acrearea);

            cout << "This amount of snow equals " << fixed << showpoint << setprecision(1) << gallons << " gallons of water." << endl << endl;
       }
    }
    while (snowdepth > 0);
    
    cout << "Enjoy the snow!" << endl;

    cout.ignore(numeric_limits<streamsize>::max(),'\n');
    cout << "Press any key to continue...." << endl;
    cout.get();

    return 0;
}

double getGallons(float snowdepth,float acrearea)
{
    const int WATER_GALLONS = 27154;
    return snowdepth * acrearea * WATER_GALLONS;
}