C++ - 返回对象的函数

Question

// Assume class definition for Cat is here.

Cat makeCat() {
    Cat lady = new Cat("fluffy");
    return lady;
}

int main (...) {
    Cat molly = makeCat();
    molly->eatFood(); 
    return 0;
}

molly->eatFood()会出现“use after free”错误吗？

Answer 1

更正了您的程序并创建了 class Cat 的示例实现:

#include <iostream>
#include <string>

class Cat {
public:
        Cat(const std::string& name_ = "Kitty")
        : name(name_)
        {
                std::cout << "Cat " << name << " created." << std::endl;
        }
        ~Cat(){
                std::cout << "Cat " << name << " destroyed." << std::endl;
        }
        void eatFood(){
                std::cout << "Food eaten by cat named " << name << "." << std::endl;
        }
private:
        std::string name;
};

Cat* makeCat1() {
        return new Cat("Cat1");
}

Cat makeCat2() {
        return Cat("Cat2");
}

int main (){
        Cat kit = makeCat2();
        kit.eatFood();

        Cat *molly = makeCat1();
        molly->eatFood();
        delete molly;

        return 0;
}

它将产生输出:

Cat Cat2 created.
Food eaten by cat named Cat2.
Cat Cat1 created.
Food eaten by cat named Cat1.
Cat Cat1 destroyed.
Cat Cat2 destroyed.

我建议你在继续之前学习一本关于 C++ 封面的基础书籍。