Question

我必须创建一个将执行所有处理的函数（billsHundred到coinLoonie计算），但输入和输出到控制台仍将在int main中完成。我该怎么做呢我真的遇到了从函数int cash（）生成多个输出的问题，所以我把它留空，以便看看你们的建议。

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

int cash();

int main()
{
    int dollarAmount;

    for (int i = 1; i <= 3; i++)
    {
        cout << "Enter the total dollar amount: $";
        cin >> dollarAmount;

        while (cin.fail())
        {
            cout << "\nThat entry is not valid. Please try again: ";
            cin.clear();
            cin.ignore(1000, '\n');
            cin.clear();
            cin >> dollarAmount;
        }

        int billsHundred = dollarAmount / 100;
        int billsFifty = (dollarAmount - (100 * billsHundred)) / 50;
        int billsTwenty = (dollarAmount - (100 * billsHundred) - (50 *  billsFifty)) / 20;
        int billsTen = (dollarAmount - (100 * billsHundred) - (50 * billsFifty) - (20 * billsTwenty)) / 10;
        int billsFive = (dollarAmount - (100 * billsHundred) - (50 * billsFifty) - (20 * billsTwenty) - (10 * billsTen)) / 5;
        int coinToonie = (dollarAmount - (100 * billsHundred) - (50 * billsFifty) - (20 * billsTwenty) - (10 * billsTen) - (5 * billsFive)) / 2;
        int coinLoonie = (dollarAmount - (100 * billsHundred) - (50 * billsFifty) - (20 * billsTwenty) - (10 * billsTen) - (5 * billsFive) - (2 * coinToonie)) / 1;

        cout << "\nNumber of 100$ bills = " << billsHundred;
        cout << "\nNumber of 50$ bills = " << billsFifty;       
        cout << "\nNumber of 20$ bills = " << billsTwenty;      
        cout << "\nNumber of 10$ bills = " << billsTen;     
        cout << "\nNumber of 5$ bills = " << billsFive;     
        cout << "\nNumber of Toonies = " << coinToonie;     
        cout << "\nNumber of Loonies = " << coinLoonie << endl << endl;
    }
    cout << endl;
    return 0;
}

int cash()
{


}

Answer 1

基本上有两种方法可以返回多个值。您要么返回struct或class作为返回值，要么传入引用值或指针，该函数设置引用/指向的值。

所以如果你必须将金额分成10s和1s：

struct Change {
    int Tens;
    int Ones;
};

Change cash(int amount) {
    Change result;
    result.Tens = amount / 10;
    result.Ones = amount % 10;
    return result;
}

Change broken = break(15);
// Refer to broken.Tens and broken.Ones.

可替换地：

void cash(int amount, int& tens, int& ones) {
    tens = amount/10;
    ones = amount%10;
}

int tens;
int ones;
cash(15, tens, ones);

在你的应用程序中，我会使用struct - 一个带有七个输出参数的函数有太多的参数。

Answer 2

要回答您的问题，您无法从C ++中的函数返回多个值。相反，您可以返回包含或引用多个内容的结构或其他对象。例如：

#include <iostream>

struct Foo {
    int x;
    int y;
};

Foo doSomething() {
    Foo f;
    f.x = 10;
    f.y = 20;
    return f;
}

int main()
{
    Foo f = doSomething();
    std::cout <<  f.x << std::endl;
    std::cout << f.y << std::endl;
}

基于上面的其余代码，我认为可以更好地调用多个函数（getBillsHundred()等），或者每个函数使用不同的参数（getBillsBySize()）不同的尺寸。每个函数都只返回一个值。

Answer 3

您可以考虑使用地图。

std::map<string, int> cash(int dollarAmount) {
    std::map<string, int> ret;
    ret['hundred'] = dollarAmount / 100;
    // stuff similar
    return ret;
}

使用函数返回多个值C ++

3 个答案: