NYU CS-UY 2124 复习

#include <iostream>
using namespace std;

class Derived;

class Base {
public:
    virtual void method(Base& arg) {
        std::cout << "Base::method(Base)\n";
    }
    virtual void method(Derived& arg) {
        std::cout << "Base::method(Derived)\n";
    }
};

class Derived : public Base {
public:
    void method(Base& arg) {
        std::cout << "Derived::method(Base)\n";
    }
    void method(Derived& arg) {
        std::cout << "Derived::method(Derived)\n";
    }
};

void someFunc(Base& argA, Base& argB) {
    argA.method(argB);
}

int main() {
    Derived d;
    Base b;
    someFunc(b, d);
}

#include <iostream>
#include <vector>

int main() {
    std::vector<int> intVec = {1, 2, 3, 4, 5};

    for (int& num: intVec) {
        /*
         * 在 C++ 中，int& 表示对 int 类型的引用。通过使用引用，我们可以直接操作 intVec 中的元素，而不是创建一个元素的副本。
         * 当我们通过引用（int&）遍历 intVec 时，对 num 所做的任何修改都将影响到 intVec 中的对应元素。
         * */
        num *= 2;
    }

    for (int num: intVec) {
        std::cout << num << " ";
    }

    return 0;
}

class FederationStarship {
public:
    FederationStarship() {}
    void attack() { std::cout << "FederationStarship firing phasers\n"; }
};

class Constitution : public FederationStarship {
public:
    virtual void transport() { std::cout << "Beam me up!\n"; }
    void attack() { std::cout << "Constitution firing phasers\n"; }
};

int main() {
    FederationStarship* NCC = new Constitution();
    NCC->transport(); // 这里将调用 Constitution::transport()
}

#include <iostream>

class FederationStarship {
public:
    FederationStarship() {}
    virtual void transport() {} // 添加 transport 方法的定义
    virtual void attack() { std::cout << "FederationStarship firing phasers\n"; }
};

class Constitution : public FederationStarship {
public:
    void transport() override { std::cout << "Beam me up!\n"; }
    void attack() override { std::cout << "Constitution firing phasers\n"; }
};

int main() {
    FederationStarship* NCC = new Constitution();
    NCC->transport(); // 将调用 Constitution::transport()，输出 "Beam me up!"
}

#include <iostream>

class Member {
public:
    Member() { std::cout << 1; }
    ~Member() { std::cout << 2; }
};

class Base {
    Member member;

public:
    Base() { std::cout << 3; }
    ~Base() { std::cout << 4; }
};

class Derived : public Base {
public:
    Derived() { std::cout << 5; }
    ~Derived() { std::cout << 6; }
};

int main() {
    Derived der;
}