复制构造函数的调用

以下例子构造函数将被调用一次，复制构造函数将被调用四次。

 

#include "iostream"

 

using namespace std;
class CA
{
public:
 CA(){ cout<< "construct be called." << endl;}
 CA(CA& ra){ cout << "copy construct be called. "<< endl;}

};

CA fun(CA a)
{
 CA na(a);

 return na;
}

int main(int argc, char* argv[])
{

 CA fa;
 
 CA fb = fun(fa);

 

 return 0;
}

 

输出结果：

 

construct be called

copy construct be called

copy construct be called

copy construct be called

copy construct be called