關於建構函式和複製建構函式以及過載的複製操作何時會被呼叫，我做了一個小例子來進行測試。

#include <iostream>

using namespace std;

class AAA
{
public:
    AAA()
    {
        cout<<"constrctor"<<endl;
    }
    AAA(const AAA & a)
    {
        cout<<"copy constrctor"<<endl;
    }
    AAA(int i)
    {
        cout
 
<<"paramter constrctor"<<endl;
    }

    AAA& operator =(const AAA & a)
    {
        cout<<"copy function"<<endl;
        return *this;
    }
};
int main()
{
    cout<<"a1:";
    AAA a1(3);
    cout<<"a2:";
    AAA a2 = AAA(4);
    cout<<"a3:";
    AAA a3=AAA();
    cout
 
<<"a4:";
    AAA a4(a2);
    cout<<"a5:";
    AAA a5;
    a5=a3;
    cout<<"a6:";
    AAA a6=a5;
    cout<<"a7:";
    AAA *a7=new AAA(1);
    cout<<"a8:";
    AAA *a8=new AAA();
    return 0;
}

由此可以看出幾點：
1、AAA a（）;和AAA a=AAA（）;是完全等價的（當然AAA a（1）;和AAA a=AAA（1）;也是相同的）；
2、對於
AAA a5;
AAA a6=a5;