C++中的枚举

#include<iostream>
#include<iomanip>
using namespace std;
int main() {
    enum color_set { red, yellow, blue, white, black }; //声明枚举类型color
    color_set color;
    int i, j, k, counter = 0, loop; //counter是累计不同颜色的组合数
    for (i = red; i <= black; i++) 
    {
        for (j = red; j <= black; j++) 
        {
            if (i != j)
            {                        //前两个球颜色不同
                for (k = red; k <= black; k++)
                    if (k != i && k != j) 
                    {        //第三个球不同于前两个，满足要求
                        counter++;
                        if ((counter) % 22 == 0) 
                        { //每屏显示22行
                            cout << "请按回车键继续";
                            cin.get();
                        }
                        cout << setw(15) << counter;
                        /*下面输出每种取法，一行为一种取法的三个颜色*/
                        for (loop = 1; loop <= 3; loop++) 
                        {
                            switch (loop)
                            {
                            case 1: color = (color_set)i; break;    //第一个是i
                            case 2: color = (color_set)j; break;    //第二个是j
                            case 3: color = (color_set)k; break;    //第三个是k
                            }
                            switch (color) 
                            {
                            case red:   cout << setw(15) << "red";   break;
                            case yellow:cout << setw(15) << "yellow"; break;
                            case blue:  cout << setw(15) << "blue";  break;
                            case white:    cout << setw(15) << "white"; break;
                            case black: cout << setw(15) << "black"; break;
                            }
                        }
                        cout << endl;            //输出一种取法后换行
                    }
            }
        }
    }
    cout << "共有：" << counter << "种取法" << endl;
    getchar();
    return 0;
}

参考：http://www.runoob.com/w3cnote/cpp-enum-intro.html