what does g++ want from my code

what does g++ want from my code

Elazar Leibovich elazarl at gmail.com
Wed Aug 25 15:05:33 IDT 2010


For further explanation about the need for typename look at
http://www.parashift.com/c++-faq-lite/templates.html#35.18
<http://www.parashift.com/c++-faq-lite/templates.html#35.18>Item 35.18

On Wed, Aug 25, 2010 at 12:33 PM, Erez D <erez0001 at gmail.com> wrote:

>
>
> On Wed, Aug 25, 2010 at 12:08 PM, Elazar Leibovich <elazarl at gmail.com>wrote:
>
>> template <class a, class b>
>>
>> class c
>>
>> {
>>
>>       private:
>>
>>               b defaultVal;
>>
>>       public:
>>
>>               std::map<a,b> mymap;
>>
>>              const b &func(a idx)
>>
>>
>>               {
>>
>>                  typename std::map<a,b>::iterator it(mymap.find(idx));
>>
>>                      if (it!=mymap.end())
>>
>>                              return it->second;
>>
>>                      else
>>
>>                              return defaultVal;
>>
>>              }
>>
>> };
>>
>>
>> The compiler is not sure std::map<a,b>::iterator is a typename or a value.
>>
> how do i sove that ? can you give a solution ?
>
>>
>> 2010/8/25 Erez D <erez0001 at gmail.com>
>>
>>> hi
>>>
>>>
>>> i am compiling the following code:
>>>
>>> 1:#include <map>
>>> 2:
>>> 3:template <class a, class b>
>>> 4:class c
>>> 5:{
>>> 6:      private:
>>> 7:              b defaultVal;
>>> 8:      public:
>>> 9:              std::map<a,b> mymap;
>>> 10:             const b &func(a idx)
>>> 11:             {
>>> 12:                     std::map<a,b>::iterator it=mymap.find(a);
>>> 13:                     if (it!=mymap.end())
>>> 14:                             return it->second;
>>> 15:                     else
>>> 16:                             return defaultVal;
>>> 17:             }
>>> 18:};
>>> ...
>>> ...
>>>
>>> compiling it (under cygwin) , i get the following:
>>>
>>> $ g++ -c -o kaka.o kaka.cpp
>>> kaka.cpp: In member function 'const b& c<a, b>::func(a)':
>>> kaka.cpp:12: error: expected `;' before 'it'
>>> kaka.cpp:13: error: 'it' was not declared in this scope
>>>
>>>
>>> what's wrong ?
>>>
>>> _______________________________________________
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>>>
>>>
>>
>
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