std :: map <> ::迭代器错误

Question

I am creating a map:

std::map<TString, TString> cuts;

where TString is a ROOT framework class that stores strings as char* (and has some additional features) that I add to my C++ code with #include "TString.h" ,

I then create a few cuts map elements:

cuts["cTRIGem0"] = "eminusL0ElectronDecision_TOS>0";

And then try to create an iterator to loop over cuts:

std::map<TSring, TSring>::iterator itr = cuts.begin();

This yields a host of errors:

Wenu.cpp:561:12: error: ‘TSring’ was not declared in this scope
Wenu.cpp:561:26: error: template argument 1 is invalid
Wenu.cpp:561:26: error: type/value mismatch at argument 2 in template parameter list for ‘template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map’
Wenu.cpp:561:26: error:   expected a type, got ‘TSring’
Wenu.cpp:561:26: error: template argument 3 is invalid
Wenu.cpp:561:26: error: template argument 4 is invalid
Wenu.cpp:561:38: error: expected initializer before ‘itr’

I saw somewhere that the keyword typename may help. So I added it to the iterator declaration:

std::map<typename TSring, typename TSring>::iterator itr = cuts.begin();

Which gave a new error:

Wenu.cpp:561:44: error: wrong number of template arguments (1, should be 4)
/cvmfs/lhcb.cern.ch/lib/lcg/external/gcc/4.6.2/x86_64-slc5/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/bits/stl_map.h:88:11: error: provided for ‘template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map’
Wenu.cpp:561:56: error: expected initializer before ‘itr’

Any help on how to resolve this error and get my iterator working would be much appreciated.

Answer 1

You spelled it wrong; you want TString , not TSring .