主要是switch语句出了问题， 只执行default语句了，不知道怎么回事，vc++6.0中。#include<iostream>
using namespace std;

enum Sys {LOW, HIGH};  //系统位数
enum Core {ONE, TWO, FOUR};//cpu单，双，四核
enum Thread {YES, NO}; //是否支持多线程

class Cpu  //Cpu类定义
{
    public:
        Cpu():frequ(0), system(LOW), core(ONE), thread(YES){}
        Cpu(int fre, Sys sys, Core co, Thread th):frequ(fre), system(sys), core(co), thread(th){}
        void show(void);
    private:
        unsigned int frequ : 12;
        Sys system : 1;
        Core core : 2;
        Thread thread : 1;
};

void Cpu::show(void)
{
    cout<<"the cpu information is:"<<endl;
    cout<<"frequency(MHz):"<<frequ<<endl;

    cout<<"the system is:"<<endl;
    switch(system)
    {
        case LOW:
                    cout<<"32bit"<<endl;
                    break;
        case HIGH:
                    cout<<"64bit"<<endl;
                    break;
        default:
                    cout<<"information error!"<<endl;
    }

    cout<<"the core is"<<endl;
    switch(core)
    {
        case ONE:
                cout<<"single core"<<endl;
                break;
        case TWO:
                cout<<"double cores"<<endl;
                break;
        case FOUR:
                cout<<"double double cores"<<endl;
                break;
        default:
                cout<<"information error!"<<endl;
    }

    cout<<"the cpu support over thread:"<<endl;
    switch(thread)
    {
        case YES:
                cout<<"yes"<<endl;
                break;
        case NO:
                cout<<"no"<<endl;
                break;
        default:
                cout<<"information error!"<<endl;
    }
}

int main(void)
{
    Cpu c(2000, HIGH, FOUR, NO);

    c.show();

    cout<<"the size of the class is:"<<sizeof(Cpu)<<endl;

    return 0;
}

        unsigned int frequ : 12;
        Sys system : 1;
        Core core : 2;
        Thread thread : 1;
改为
        unsigned int frequ : 12;
        unsigned int system : 1;
        unsigned int core : 2;
        unsigned int thread : 1;

还有个问题，就是字节数测出来为什么是4呢，应该是2吧。

为什么要那样改呢， 那几个不是枚举类型变量吗， 为什么定义为unsigned int呢？

不知道是不是这样改 这样改能显示正常
#include<iostream>
using namespace std;

enum Sys {LOW, HIGH};  //系统位数
enum Core {ONE, TWO, FOUR};//cpu单，双，四核
enum Thread {YES, NO}; //是否支持多线程

class Cpu  //Cpu类定义
{
public:
    Cpu():frequ(0), system(LOW), core(ONE), thread(YES){}
    Cpu(int fre, Sys sys, Core co, Thread th):frequ(fre), system(sys), core(co), thread(th){}
    void show();
private:
    int frequ ;//: 12;
    int system ;//: 1;
    int core ;//: 2;
    int thread ;//: 1;
};

void Cpu::show(void)
{
    cout<<"the cpu information is:"<<endl;
    cout<<"frequency(MHz):"<<frequ<<endl;   
    cout<<"the system is:"<<endl;
    switch(system)
    {
    case 0:
        cout<<"32bit"<<endl;
    break;
    case 1:
            cout<<"64bit"<<endl;
        break;
        default:
            cout<<"information error!"<<endl;
    }
    cout<<"the core is"<<endl;
    switch(core)
    {
    case ONE:
        cout<<"single core"<<endl;
        break;
    case TWO:
        cout<<"double cores"<<endl;
        break;
    case FOUR:
        cout<<"double double cores"<<endl;
        break;
    default:
        cout<<"information error!"<<endl;
    }
   
    cout<<"the cpu support over thread:"<<endl;
    switch(thread)
    {
    case YES:
        cout<<"yes"<<endl;
        break;
    case NO:
        cout<<"no"<<endl;
        break;
    default:
        cout<<"information error!"<<endl;
    }
}

int main()
{
    Cpu c(2000, HIGH, FOUR, NO);
   
    c.show();
   
    cout<<"the size of the class is:"<<sizeof(Cpu)<<endl;
   
    return 0;
}