c++ - 我如何根据可迭代对象进行案例陈述？

Question

我想基于可迭代对象做一个 case 语句，但我知道 case 表达式必须是一个常量。有什么解决方法？

我试了下面的代码，还是不行。

#include <iostream>
using std::cout;
using namespace std;

int main()
{
    int i = 0;
    while( i >= 0)
    {
        const int z = i;
        cout << "Enter a number other than " << z << "!\n";
        int choice;
        cin >> choice;
        switch(choice){
            case z: cout << "Hey! you weren't supposed to enter "<< z <<"!"; return 0; break;
            default: if(i==10)
                    {
                        cout << "Wow, you're more patient then I am, you win."; return 0;
                    }
                    break;
        }
        i++;
    }

}

Answer 1

case 需要在编译时已知的常数整数值。

所以你必须使用if-s:

if (choice == z) {
  cout << "Hey! you weren't supposed to enter "<< z <<"!";
  return 0;
} else if (i == 10) {
  cout << "Wow, you're more patient then I am, you win.";
  return 0;
}