class TEST{
private :
public :
TEST() {std::cout << "constructor" << std::endl; }
~TEST() {std::cout << "destructor" << std::endl; }
};
class TEST fun(void)
{
TEST t, tt;
return t;
}
int main()
{
class TEST t = fun();
std::cout << "test...test" << std::endl;
}
$ ./pointer_reference
constructor
constructor
destructor
test...test
destructor //main函数中创建 t 实际上就是复制
class TEST{
private :
public :
TEST() {std::cout << "constructor" << std::endl; }
~TEST() {std::cout << "destructor" << std::endl; }
};
class TEST fun(void)
{
TEST t;
TEST tt = t;
return t;
}
int main()
{
class TEST t = fun();
std::cout << "test...test" << std::endl;
}
$ ./pointer_reference
constructor
destructor //创建tt时候没有调用构造函数
test...test
destructor //t 最后被释放
class TEST{
private :
public :
TEST() {std::cout << "constructor" << std::endl; }
~TEST() {std::cout << "destructor" << std::endl; }
};
#if 0 //case 0
void fun(class TEST t)
#else //case 1
void fun(class TEST& t)
#endif
{
return;
}
int main()
{
class TEST t;
fun(t);
std::cout << "test...test" << std::endl;
}
case 0:
$ ./pointer_reference
constructor
destructor
test...test
destructor
case 1:
$ ./pointer_reference
constructor
test...test
destructor