A strange problem of template 
July 18th, 2007, 03:15 PM
| | |  A strange problem of template
Hello,
I want a use the class of map in a class with template,
and the type of elements in map is specified by the parameter of the
class's template.
For example,
template <typename key, typename T>
class hashmap
{
map<key , Ttable;
public:
void find(const key &k){
map<key,T>::iterator it=table.find(k); <=the error
}
};
int main()
{
hashmap<int,inthm;
}
When I compile it, I get the error
test.cc:33: error: expected `;' before 'it'
I don't get it. Why I can use map in this class, but I can't define its
iterator?
Zheng Da
--
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July 18th, 2007, 03:25 PM
| | | Re: A strange problem of template
Zheng Da wrote: Quote:
I want a use the class of map in a class with template,
and the type of elements in map is specified by the parameter of the
class's template.
For example,
template <typename key, typename T>
class hashmap
{
map<key , Ttable;
public:
void find(const key &k){
map<key,T>::iterator it=table.find(k); <=the error
}
};
>
int main()
{
hashmap<int,inthm;
}
>
When I compile it, I get the error
test.cc:33: error: expected `;' before 'it'
I don't get it. Why I can use map in this class, but I can't define
its iterator?
| Read up on 'typename' keyword and where it's supposed to be used.
(Hint: there are FAQ entires that have it and there is more than one
use of that keyword)
V
--
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July 18th, 2007, 08:15 PM
| | | Re: A strange problem of template
Victor Bazarov wrote: Quote:
Zheng Da wrote: Quote:
>I want a use the class of map in a class with template,
>and the type of elements in map is specified by the parameter of the
>class's template.
>For example,
>template <typename key, typename T>
>class hashmap
>{
>map<key , Ttable;
>public:
>void find(const key &k){
>map<key,T>::iterator it=table.find(k); <=the error
>}
>};
>>
>int main()
>{
>hashmap<int,inthm;
>}
>>
>When I compile it, I get the error
>test.cc:33: error: expected `;' before 'it'
>I don't get it. Why I can use map in this class, but I can't define
>its iterator?
| >
Read up on 'typename' keyword and where it's supposed to be used.
(Hint: there are FAQ entires that have it and there is more than one
use of that keyword)
>
V
| I'm sorry, I really didn't find the solution.
You mean http://www.parashift.com/c++-faq-lite/templates.html?
I didn't find the similar question there.
I tried to use 'typename' as keyword to search c++ faq, and still didn't
find the similar questions.
Zheng Da
--
Posted via a free Usenet account from http://www.teranews.com |
July 18th, 2007, 08:25 PM
| | | Re: A strange problem of template
Zheng Da wrote: Quote:
Victor Bazarov wrote: Quote:
>Zheng Da wrote: Quote:
>>I want a use the class of map in a class with template,
>>and the type of elements in map is specified by the parameter of the
>>class's template.
>>For example,
>>template <typename key, typename T>
>>class hashmap
>>{
>>map<key , Ttable;
>>public:
>>void find(const key &k){
>>map<key,T>::iterator it=table.find(k); <=the error
>>}
>>};
>>>
>>int main()
>>{
>>hashmap<int,inthm;
>>}
>>>
>>When I compile it, I get the error
>>test.cc:33: error: expected `;' before 'it'
>>I don't get it. Why I can use map in this class, but I can't define
>>its iterator?
| >>
>Read up on 'typename' keyword and where it's supposed to be used.
>(Hint: there are FAQ entires that have it and there is more than one
> use of that keyword)
>>
>V
| >
I'm sorry, I really didn't find the solution.
You mean http://www.parashift.com/c++-faq-lite/templates.html?
I didn't find the similar question there.
I tried to use 'typename' as keyword to search c++ faq, and still
didn't find the similar questions.
| You know what, I don't want to prove you wrong or prove myself wrong.
Just do
typename map<key,T>::iterator it = ...
And get a decent book on C++ templates that explains the need for the
'typename' keyword, OK?
V
--
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I do not respond to top-posted replies, please don't ask |
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