Help wanted on operator overloading

[Magcialking]

template<class T>
ostream& operator<< (ostream& out, const list<T>& lst) {
for (list<T>::const_iterator ref = lst.begin(); ref !=
lst.end();ref++)
/*Compiler says here, ';' shoud occur before ref,and ref is not
declared,but I really don't know what's the problem here*/
out << *ref;
return out;
}

 

[mimi]

"Magcialking дµÀ£º
"

template<class T>
ostream& operator<< (ostream& out, const list<T>& lst) {
for (list<T>::const_iterator ref = lst.begin(); ref !=
lst.end();ref++)
/*Compiler says here, ';' shoud occur before ref,and ref is not
declared,but I really don't know what's the problem here*/
out << *ref;
return out;
}

Have you include the header file <list>.
The following code works fine in my compiler.

#include <list>
#include <iostream>
using namespace std;

template<class T>
ostream& operator<< (ostream& out, const list<T>& lst) {
for (list<T>::const_iterator ref = lst.begin(); ref !=
lst.end();ref++)
std::cout << *ref << "\n";
return out;
}


int main()
{
list<int> a;
a.push_back(1);
cout << a;
return 0;
}

 

[Magcialking]

I'm sure I left nothing.
And the code you give doesn't work in my compliler(Mingw)

"mimi дµÀ£º
"

 

[Magcialking]

I'm sure I left nothing.
And the code you give doesn't work in my compliler(Mingw)

"mimi дµÀ£º
"

 

[Bo Yang]

Magcialking :

template<class T>
ostream& operator<< (ostream& out, const list<T>& lst) {
for (list<T>::const_iterator ref = lst.begin(); ref !=
lst.end();ref++)
/*Compiler says here, ';' shoud occur before ref,and ref is not
declared,but I really don't know what's the problem here*/
out << *ref;
return out;
}

I have compile your code with mingw, and it produce the same
error! The root of the error is that the compiler look
list<T>::const_iterator as a dependent name. So you need to
do

for( typename list<T>::const_iterator ref ...)

and everything is OK!

 

[mimi]

"Bo Yang дµÀ£º
"

Magcialking :

I am sorry. Maybe I should uninstall my VC 6.0 immediately.

 

[Magcialking]

Thanx a lot, both of you!