枚举类型

例1.enum BUS{going, went, stay, broke}

(1)枚举类型元素为常量，不可对其赋值

如    going=9   就是错误的

但是枚举类型可在其内部对其进行赋值

例2.enum BUS{going=9, went, stay, broke}

为正确的

(2)枚举类型具有默认值，

如例1中 going=0，went=1,  stay=2,  broke=3

例2中 going=9，其后值为前一值加一，即went=10,stay=11,broke=12

(3)整数值不可直接赋值给枚举变量，若需要将整数值赋值给枚举变量，则必须进行强制转换

如

BUS state;

int i = 2;

state = BUS(i);

为正确赋值方法

（同样也可以使用state = static_cast<BUS>(i)进行赋值）

#include<iostream>
using namespace std;
enum BUS{going,went,stay,broke};
void main()
{
    BUS state;
    enum BUS omit = broke;
    for(int count=going; count<=broke; ++count)　　//枚举元素值可不经转换直接赋值给整形变量
    {
        state = BUS(count);　　　　　　　　　　　　　　//整型变量给枚举类型赋值则必须强制转能换
        if(state == omit)
            cout<<"Bus was broke."<<endl;
        else
        {
            cout<<"Bus was Ok";
            if(state == going)
                cout<<" and will going."<<endl;
            else if(state == went)
                cout<<" and was went."<<endl;
            else
                cout<<" and was stay."<<endl;
        }
    }
}