|
#2
rjsp2017-06-29 08:26
我帮你去掉和问题屁关系都没有的代码，并按照正常人风格修改了一下
 程序代码：#include <iostream> class Demo { public: Demo( int id ) : id_(id) { std::cout << "Address=" << this << " id = " << id_ << " Constructed" << std::endl; } Demo( const Demo& d ) : id_(d.id_) { std::cout << "Address=" << this << " id = " << id_ << " Copy Constructed" << std::endl; } Demo& operator=( const Demo& d ) { id_ = d.id_; std::cout << "Address=" << this << "<--" << &d << " id = " << id_ << " Assign Operator" << std::endl; return *this; } ~Demo() { std::cout << "Address=" << this << " id = " << id_ << " Destructed" << std::endl; } protected: int id_; }; using namespace std; int main( void ) { Demo d4(4); d4 = 6; return 0; } 输出 Address=0012FF6C id = 4 Constructed Address=0012FF68 id = 6 Constructed Address=0012FF6C<--0012FF68 id = 6 Assign Operator Address=0012FF68 id = 6 Destructed Address=0012FF6C id = 6 Destructed |
源代码如下：
#include <iostream>
using namespace std;
class Demo {
int id;
public:
Demo(int i)
{
id = i;
cout << "id = " << id << " Constructed" << endl;
}
~Demo()
{
cout << "id = " << id << " Destructed" << endl;
}
};
Demo d1(1);
void Func() {
static Demo d2(2);
Demo d3(3);
cout << "Func" << endl;
}
int main() {
Demo d4(4);
d4 = 6;
cout << "main" << endl;
{ Demo d5(5); }
Func();
cout << "main ends" << endl;
return 0;
}
输出如下：
id=1 Constructed
id=4 Constructed
id=6 Constructed
id=6 Destructed
main
id=5 Constructed
id=5 Destructed
id=2 Constructed
id=3 Constructed
Func
id=3 Destructed
main ends
id=6 Destructed
id=2 Destructed
id=1 Destructed
我不明白为什么出现了三次 id=6，请各位指导一下。