c++ - 使用 C++ 模数运算符的票据面额

Question

请帮帮我!我的 C++ 程序似乎有错误。代码显示关于面额的错误输出，给定一个整数比索作为输入。编写一个程序，显示 1000、500、100、50、20 和 10 比索纸币的数量。输出所有面额后的剩余金额。

这是我的程序代码。

#include <iostream>

using namespace std;

int main()
{
    int a;
    cout << "Enter the amount: ";
    cin  >> a;

    cout << "No. of 1000 peso bills:  "  << a/1000;
    cout << "\nNo. of 500  peso bills:  "  << a%1000/500;
    cout << "\nNo. of 100  peso bills:  "  << a%500/100;
    cout << "\nNo. of 50   peso bills:  "  << a%100/50;
    cout << "\nNo. of 20   peso bills:  "  << a%50/20;
    cout << "\nNo. of 10   peso bills:  "  << a%20/10;
    cout << "\n\nThe rest of the amount: " << a%10;
}

输出显示:

Enter the amount: 34757
No. of 1000 peso bills:  34
No. of 500  peso bills:  1
No. of 100  peso bills:  2
No. of 50   peso bills:  1
No. of 20   peso bills:  0
No. of 10   peso bills:  1

The rest of the amount: 7

Process returned 0 (0x0)   execution time : 2.156 s
Press any key to continue.

10 比索钞票的数量必须是 0 而不是 1，我该如何更正此问题？提前致谢。

Answer 1

问题是数学。由于 50 不是 20 的倍数，因此您需要修正 10 比索钞票的计算:

(a%50-(a%50)/20*20)/10;

这当然只是针对这种特定情况的解决方案。一般来说，如果你有其他账单，事情就更复杂了。在您的情况下，您很幸运，因为大多数钞票都是所有较小钞票的精确倍数，其中 50/20 对是唯一的异常(exception)。

---

一个更通用和可读的解决方案，灵感来自另一个答案:

#include <iostream>
using namespace std;

int main()
{
    int a;
    cout << "Enter the amount: ";
    cin  >> a;

    cout << "No. of 1000 peso bills:  "  << a/1000;
    cout << "\nNo. of 500  peso bills:  "  << (a%=1000)/500;
    cout << "\nNo. of 100  peso bills:  "  << (a%=500)/100;
    cout << "\nNo. of 50   peso bills:  "  << (a%=100)/50;
    cout << "\nNo. of 20   peso bills:  "  << (a%=50)/20;
    cout << "\nNo. of 10   peso bills:  "  << (a%=20)/10;
    cout << "\n\nThe rest of the amount: " << a%10;
}