hash_map with string keys :"instantiated from here" error & STL questions

[Konstantinos Pachopoulos]

Hi,
Greetings; that my first gcc post. Here's the code, that causes the error.


FinancialProductsMatrix.h:

class FinancialProductsMatrix
{
    private:
...
        //maps currency names(ISO namings) to a specific row and column 
        //of the matrix (row_num==col_num)
        hash_map<string,int> fProductToId_;
...
        double getEquivalance4MatrixId(int row, int column); //private method
...

    public:

        //get the (fromProduct->toProduct) equivalance value
        double getEquivalance4ISONames(string fromProduct,string toProduct);
}



FinancialProductsMatrix.cc

double FinancialProductsMatrix::getEquivalance4MatrixId(int row, int column)
{
    if (row < column)
    {
       return (double)equivMatrix_[2*row+column-1];
    }    
    else
    {
        return (double)(1/equivMatrix_[2*column+row-1]);
    }
}//getEquivalance4MatrixId


double FinancialProductsMatrix::getEquivalance4ISONames(string fromProduct,string toProduct)
{    
    //THIS IS WHERE I GET THE ERROR!
    return (double)getEquivalance4MatrixId( (int)(fProductToId_[fromProduct]), (int)(fProductToId_[toProduct]) );
}//getEquivalance4ISONames



Compiling it, i get:

...
Running "make -f nbproject/Makefile-Debug.mk build/Debug/GNU-Generic/FinancialProductsMatrix.o" in /shared/kostas/programming/c++/arbigames

mkdir -p build/Debug/GNU-Generic
g++    -c -g -o build/Debug/GNU-Generic/FinancialProductsMatrix.o FinancialProductsMatrix.cc
In file included from /usr/include/c++/4.1.3/backward/hash_map.h:59,
                 from FinancialProductsMatrix.h:4,
                 from FinancialProductsMatrix.cc:1:
/usr/include/c++/4.1.3/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated.
/usr/include/c++/4.1.3/ext/hashtable.h: In member function ‘size_t __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num_key(const _Key&, size_t) const [with _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>, _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _HashFcn = __gnu_cxx::hash<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _ExtractKey = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int> >, _EqualKey = std::equal_to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<int>]’:
/usr/include/c++/4.1.3/ext/hashtable.h:600:   instantiated from ‘size_t __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num(const _Val&, size_t) const [with _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>, _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _HashFcn = __gnu_cxx::hash<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _ExtractKey = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int> >, _EqualKey = std::equal_to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<int>]’
/usr/include/c++/4.1.3/ext/hashtable.h:1007:   instantiated from ‘void __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::resize(size_t) [with _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>, _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _HashFcn = __gnu_cxx::hash<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _ExtractKey = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int> >, _EqualKey = std::equal_to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<int>]’
/usr/include/c++/4.1.3/ext/hashtable.h:795:   instantiated from ‘typename __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::reference __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::find_or_insert(const _Val&) [with _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>, _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _HashFcn = __gnu_cxx::hash<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _ExtractKey = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int> >, _EqualKey = std::equal_to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<int>]’
/usr/include/c++/4.1.3/ext/hash_map:233:   instantiated from ‘_Tp& __gnu_cxx::hash_map<_Key, _Tp, _HashFcn, _EqualKey, _Alloc>::operator[](const typename __gnu_cxx::hashtable<std::pair<const _Key, _Tp>, _Key, _HashFcn, std::_Select1st<std::pair<const _Key, _Tp> >, _EqualKey, _Alloc>::key_type&) [with _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Tp = int, _HashFcn = __gnu_cxx::hash<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _EqualKey = std::equal_to<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<int>]’
FinancialProductsMatrix.cc:125:   instantiated from here
/usr/include/c++/4.1.3/ext/hashtable.h:596: error: no match for call to ‘(const __gnu_cxx::hash<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >) (const std::basic_string<char, std::char_traits<char>, std::allocator<char> >&)’
make: *** [build/Debug/GNU-Generic/FinancialProductsMatrix.o] Error 1

Build failed. Exit value 2.



1/I got an answer, that the error has to do with hash_map not being able 
to handle string objects. First, can somebody confirm that?
2/I read somewhere, that hash_map is not "standard". What does this 
mean? Doesn't libstdc++ implement the sgi STL "standard"?

Is this the answer? :)


    5.3 What about the STL from SGI?

The STL from SGI <http://www.sgi.com/tech/stl/>, version 3.3, was the 
final merge of the STL codebase. The code in libstdc++ contains many 
fixes and changes, and the SGI code is no longer under active 
development. We expect that no future merges will take place.

In particular, |string| is not from SGI and makes no use of their "rope" 
class (which is included as an optional extension), nor is |valarray| 
and some others. Classes like |vector<>| are, however we have made 
significant changes to them since then.

The FAQ for SGI's STL (one jump off of their main page) is recommended 
reading.



3/ If this is the answer, where can i find an libstdc++ API, that 
contains the libstdc++ STL API as well? Maybe something the SUN JDK API -yes
i am a Java coder wanting to learn C++...

4/Then i followed this sgi STL example: 
http://www.sgi.com/tech/stl/hash_map.html, which didn't work.
Since i am now learning C++, can somebody tell me what i must and 
explain a little? or point me to a link about this issue?

Thanks a lot everybody