Question

我无法弄清楚如何重复此程序，因此用户可以输入另一组小时。

我是否需要将此更改为＆＃34; Do ... While＆＃34;声明？

我正在考虑添加一个＆＃34;用户定义的函数＆＃34;最后，但我的教授可能不允许这样，因为我们还没有到达那里。

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

const float initialVolume = 130.00;
const float decreaseRate = 0.13;
string name;
int counter = 0;

int main()
{
    int hours,i,j,k;
    float remainingVolume, halfVolume, zeroVolume;

    cout << "Enter hours to see how much caffeine "
         << "is left in your body, after you drank your coffee: ";
    cin >> hours;
    cout << endl;
    cout << fixed << showpoint << setprecision(4);

    remainingVolume = initialVolume;

    for (i = 0; i < hours; i++)
    {
        counter++;
        remainingVolume = remainingVolume - decreaseRate * remainingVolume;
        cout << "Hour " << setw(5) << counter << setw(15) << remainingVolume << "mg"<< endl;
    }

    for (j = 0, halfVolume = 130.00; halfVolume > 65.0000; j++)
    {
        counter++;
        halfVolume = halfVolume - decreaseRate * halfVolume;
    }

    for (k = 0, zeroVolume = 130.00; zeroVolume > 0.0001; k++)
    {
        counter++;
        zeroVolume = zeroVolume - decreaseRate * zeroVolume;
    }

    cout << "\n" << endl;
    cout << "It will take " << j << " hours to get caffeine levels to 65mg. \n" << endl;
    cout << "It will take " << k << " hours to get caffeine levels to 0mg." << endl;

    return 0;
}

Answer 1

建议将工作分解为命名良好的函数，然后根据用户如何终止循环来建立循环逻辑。

Answer 2

一种简单的方法，如果出现错误读取就会终止（例如，用户键入非整数值或按下例如^D（Linux / UNIX）或^Z（Windows）生成文件结束条件：

int main()
{
    int hours,i,j,k;
    float remainingVolume, halfVolume, zeroVolume;

    while (cout << "Enter hours to see how much caffeine "
                << "is left in your body, after you drank your coffee: " &&
           cin >> hours)
    {
        cout << endl;
        cout << fixed << showpoint << setprecision(4);
        ...etc...
    }
    // no need to return 0; - that's done implicitly
}

如何在C ++中重复“for”循环

2 个答案: