类间通信-通过指向对象的指针

类间通信实例：

#include<iostream>using namespace std;class A{private:int x;public:    A(int x)    {        this->x=x;    }    void fun()    {        cout<<"A out"<<endl;    }    ~A()    {        cout<<"A Delete"<<endl;    }};class B{private: A *pa;public:    B(A *t)    {        pa=t;    }    void dofun()    {        pa->fun();    }    ~B()    {        cout<<"B Delete"<<endl;    }};

//①int main(void){    A objA(1);    B objB(&objA);    objB.dofun();    return 0;}

//②int main(void){    A objA(1);    B *pB=new B(&objA);    pB->dofun();    delete pB;    return 0;}

//③int main(void){    A *pA=new A(1);    B *pB=new B(pA);    pB->dofun();    delete pA;    delete pB;    return 0;}

//④    ~B()    {        cout<<"B Delete"<<endl;        delete pa;    }int main(void){    B *pB=new B(new A(1));    pB->dofun();    delete pB;    return 0;}

//⑤class B{private: A *pa;public:    B(int x)    {        pa=new A(x);    }    void dofun()    {        pa->fun();    }    ~B()    {        cout<<"B Delete"<<endl;        delete pa;    }};int main(void){    B *pB=new B(1);    pB->dofun();    delete pB;    return 0;}

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例1：

①#include<iostream>using namespace std;class A{private:int x;public:    A()    {        this->x=0;    }    A(int x)    {        this->x=x;    }    void fun()    {        cout<<"x="<<x<<endl;    }};class B{private:int y;public:    B()    {        this->y=0;    }    B(int y)    {        this->y=y;    }    void fun()    {        cout<<"y="<<y<<endl;    }};class C{private:int z;public:    C()    {        this->z=0;    }    C(int z)    {        this->z=z;    }    void fun()    {        cout<<"z="<<z<<endl;    }};class My{private:    A *a;    B *b;    C *c;public:    My(A *ta,B *tb,C *tc)    {        a=ta;        b=tb;        c=tc;    }    void dofun()    {        a->fun();        b->fun();        c->fun();    }};int main(void){    A *pa=new A(3);    B *pb=new B(4);    C *pc=new C(5);    My *pmy=new My(pa,pb,pc);    pmy->dofun();    //释放（new 出来的对象要用delete释放）    delete pa;    delete pb;    delete pc;    delete pmy;    return 0;}

②通过析构函数来释放~My()    {        delete a;        delete b;        delete c;    }client:    A *pa=new A(3);    B *pb=new B(4);    C *pc=new C(5);    My *pmy=new My(pa,pb,pc);    pmy->dofun();    //释放    delete pmy;    return 0;③A,B,C的指针直接new出来，必须用方式②来释放    My *pmy=new My(new A(3),new B(4),new C(5));    pmy->dofun();    delete pmy;    return 0;

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例2：如图实现，类图，如右图链式输出

#include<iostream>using namespace std;class A{private:int data;        A *next;public:    A()    {        this->data=0;        next=NULL;    }    A(int data)    {        this->data=data;        next=NULL;    }    void setNext(A *t)    {        next=t;    }    void print()    {        cout<<this->data<<endl;        if(next)            next->print();    }    ~A()    {        delete next;    }};int main(void){    int x;    A *p,*h=NULL;    //建链    for(int i=0;i<3;i++)    {        cout<<"输入数据"<<endl;        cin>>x;        p=new A(x);        p->setNext(h);//注意next为私有，不可直接调用        h=p;    }    h->print();    delete h;    return 0;}