根据C++中的外部输入选择类

#include <iostream>

// 定义类A
class A {
public:
    void doSomething() {
        std::cout << "Class A: Doing something..." << std::endl;
    }
};

// 定义类B
class B {
public:
    void doSomething() {
        std::cout << "Class B: Doing something..." << std::endl;
    }
};

int main() {
    int externalInput;
    std::cout << "Please enter an external input (1 or 2): ";
    std::cin >> externalInput;

    // 根据外部输入选择类
    if (externalInput == 1) {
        A objA;
        objA.doSomething();
    } else if (externalInput == 2) {
        B objB;
        objB.doSomething();
    } else {
        std::cout << "Invalid input!" << std::endl;
    }

    return 0;
}