C++初识对象初始化列表,与应用

这些对象都分配在栈上

//
//  main.cpp
//  拷贝构造函数
//
//  Created by Eric on 16/7/20.
//  Copyright © 2016年 Eric. All rights reserved.
//

#include <iostream>
using namespace std;
class A{
public:
    A(int a){
        _a = a;
    };
    A(int a,int b){
        _a = a;
    };
    
    A(const A& obj){
        cout<<"A 拷贝构造函数调用\n";
    }
    int getA(){
        return _a;
    }
    void setA(int a){
        _a = a;
    }
private:
    int _a;
};

class Location
{
public:
    /**
     *  含参构造函数  构造函数初始化列表
     */
    Location(int x = 0,int y = 0):a1(10){
        _x = x;
        _y = y;
        _myP = (char *)malloc(100);
        strcpy(_myP, "adfadaf");
        
        cout<<"Constructor Object.\n";
    }
    Location(const Location &obj):a1(10){
        cout<<"调用拷贝构造函数 \n";
    }
    /**
     *  析构函数
     */
    ~Location(){
        cout<<_x<<","<<"Object destroryed"<<endl;
        if (_myP != NULL) {
            free(_myP);
        }
    }
    
    int getX(){
        return _x;
    }
private:
    int _x,_y;
    
    char *_myP;
    A a1;
    
};

class B{
public:
    B(int a,int n,int m,int a2n,int a2m):a1(n,m),a2(a2n,a2m){
        _a = a;
    }
    
    A getA1(){
        return a1;
    }
    A getA2(){
        return a2;
    }
    
    void doThing(A &a){
        a.setA(100);
        printf("B 开始Do thing了\n");
    }
    
private:
    A a1;
    A a2;
    int _a;
};


int main(int argc, const char * argv[]) {
    // insert code here...
    std::cout << "Hello, World!\n";
    

    B b1 = B(1, 2, 3, 4, 5);
    A a1 = b1.getA1();
    A a2 = b1.getA2();
    printf("a1-->%d\n",a1.getA());
    printf("a2-->%d\n",a2.getA());
    
    
    b1.doThing(a1);
    printf("a1-->%d\n",a1.getA());
    
    return 0;
}