<未完>再次研究指针和引用

最新推荐文章于 2024-12-29 01:37:39 发布

原创最新推荐文章于 2024-12-29 01:37:39 发布 · 715 阅读

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CC 4.0 BY-SA版权

本文通过几个具体的函数实例，探讨了C++中不同方式传递对象对内存的影响，包括指针、引用及值传递等，并展示了如何正确地在函数内部修改对象的状态而不影响原始数据。

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#include <iostream>
using namespace std;
class apple{
public:
	int id;

public:
	apple(int id){
	   this->id = id;
	}
	void operator=(apple tmp){
		this->id = tmp.id;
	}
};
void f1(apple* app){
   app = new apple(101);
}
void f2(apple& app){
   apple* tmp = new apple(101);
   app = *tmp;
}
void f3(apple* &app){
   app = new apple(101);
}
void f4(apple app){
   apple* tmp = new apple(101);
   app = *tmp;
}
int main(){
   apple* app = new apple(100);
   apple app2 = *app;
   //f1(&app2);
   //f3(&app2);报错
   //apple* c = &app2;
   //f3(c);
   f4(app2);
   //app->id
   cout << app2.id << endl;
}
//f1:100
//f2:101
//f3:101
//f4:100
//app2
//f1:100
//f2:101
//f3:错误
//f3:100
//f4:100

#include <iostream>
using namespace std;
class apple{
public:
	int id;

public:
	apple(int id){
	   this->id = id;
	}
	void operator=(apple tmp){
		this->id = tmp.id;
	}
};
void f1(apple* app){
   //app = new apple(101);
	app->id = 101;
}
void f2(apple& app){
   apple* tmp = new apple(101);
   app = *tmp;
}
void f3(apple* &app){
   app = new apple(101);
}
void f4(apple app){
   apple* tmp = new apple(101);
   app = *tmp;
}
int main(){
   apple* app = new apple(100);
   apple app2 = *app;
   //f1(&app2);
   //f3(&app2);报错
   //apple* c = &app2;
   //f3(c);
   //f4(app2);
   //app->id
   f1(app);
   cout << app->id << endl;
}
//这个竟然输出101………………