C++自学计划-switch-09

例子：

    int type = 2;
    switch (type) {
        case 1:
            std::cout << 1 << std::endl;
            break;
        case 2://故意没写break
            std::cout << 2 << std::endl;
        case 3:
            std::cout << 3 << std::endl;
            break;
        case 4:
            std::cout << 4 << std::endl;
            break;
        default:
            std::cout << 5 << std::endl;
    }