示例一

以下是一些关于 switch、while、do…while、break 和 continue 这些知识点的C++示例代码：
1. switch 语句示例

#include <iostream>  
using namespace std;  

int main() {  
    int day;  
    cout << "请输入星期几（1-7）：";  
    cin >> day;  

    switch (day) {  
        case 1:  
            cout << "星期一" << endl;  
            break;  
        case 2:  
            cout << "星期二" << endl;  
            break;  
        case 3:  
            cout << "星期三" << endl;  
            break;  
        case 4:  
            cout << "星期四" << endl;  
            // 注意这里没有break，会导致fall-through到下一个case  
        case 5:  
            cout << "星期五或由于fall-through也执行的星期四之后的星期五" << endl;  
            break;  
        case 6:  
            cout << "星期六" << endl;  
            break;  
        case 7:  
            cout << "星期日" << endl;  
            break;  
        default:  
            cout << "无效输入" << endl;  
    }  

    return 0;  
}

2. while 循环示例

#include <iostream>  
using namespace std;  

int main() {  
    int count = 1;  

    while (count <= 5) {  
        cout << "计数：" << count << endl;  
        count++;  
    }  

    return 0;  
}

3. do…while 循环示例

#include <iostream>  
using namespace std;  

int main() {  
    int count = 1;  

    do {  
        cout << "计数（do...while）：" << count << endl;  
        count++;  
    } while (count <= 5);  

    return 0;  
}