c++ 返回值，临时变量。谁能帮忙分析以下代码。
0
悬赏园豆：10
[待解决问题]
(1)
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test F(Test x)
{ return x;}
int main()
{
Test t1;
Test t2;
t2=F(t1);
return 0;
}
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test &F(Test &x)
{ return x;}
int main(){
Test t1;
Test t2;
t2=F(t1);
return 0;
}
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test &F(Test x)
{ return x;}
int main(){
Test t1;
Test t2;
t2=F(t1);
return 0;
}
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test F(Test &x)
{ return x;}
int main(){
Test t1;
Test t2;
t2=F(t1);
return 0;
}
(2)
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test F(Test x)
{ return x;}
int main()
{
Test t1;
Test t2=F(t1);
return 0;
}
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test &F(Test &x)
{ return x;}
int main(){
Test t1;
Test t2=F(t1);
return 0;
}
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test &F(Test x)
{ return x;}
int main(){
Test t1;
Test t2=F(t1);
return 0;
}
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test F(Test &x)
{ return x;}
int main(){
Test t1;
Test t2=F(t1);
return 0;
}
所有回答(4)
0
what do you want to say?
例如
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test F(Test x)
{ return x;}
int main()
{
Test t1;
Test t2;
t2=F(t1);
return 0;
}
结果是
ctor
ctor
copy ctor
copy ctor
destory
destory
destory
destory
而
#include<iostream>
using namespace std;
class Test{
static int i;
public:
Test()
{
cout<<"ctor"<<endl;
}
Test(const Test&test)
{
cout<<"copy ctor"<<endl;}
~Test(){
cout<<"destory.."<<endl;
}
void print() { }
};
Test &F(Test &x)
{ return x;}
int main(){
Test t1;
Test t2;
t2=F(t1);
return 0;
}
结果是
ctor
ctor
destory
destory
0
表述你的问题，你那里不明白，不要一堆代码，在我们看来，这些代码的输出是很好解释的，你那里不明白？学会怎么提问，怎么清楚的表述自己的问题，这比解决一个问题更重要。
0
看看《提问的智慧》，最近总是看到有些同学没能清楚的表述自己的问题，这样别人就不能给你想要的答案了
0
我只能说提出的问题要让人容易理解怎么回答，这样才有更多的人愿意去回答。重新整理一下问题把！！！不清晰，让人无从下手的……加油！！！
