search map avoids const methods

rolcsar (2)
Hello folks,

I am trying to compile the following code: 

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#include <iostream>
#include <string>
#include <map>
using namespace std;

class cfos
{
	private:
		map<int, string> diccfo;
	public:
		void setcfo (int c, string d) const
		{
			diccfo[c] = d;
		};
		string& getcfo (int c)
		{
			return diccfo[c];
		};
		void print() const
		{
			map<int, string>::iterator pdiccfo;
			for  (pdiccfo = diccfo.begin(); 
                               pdiccfo != diccfo.end();
				++pdiccfo)
				cout << pdiccfo->first << '\t' 
                                        << pdiccfo->second 
                                        << '\n';
		};
};

int main()
{
    cfos cfocoll;
    cfocoll.setcfo(1, "one");
    cfocoll.setcfo(2, "two");
    cfocoll.print();
    cout << cfocoll.getcfo(1) << endl;
    return 0;
}

however, this error occurs:

passing ‘const std::map<int, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<int>, std::allocator<std::pair<const int, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >’ as ‘this’ argument of ‘_Tp& std::map<_Key, _Tp, _Compare, _Alloc>::operator[](const _Key&) [with _Key = int, _Tp = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >]’ discards qualifiers


Changing the map to mutable, I get to compile it, but the methods print () and setcfo () will be able to modify the map, what conceptually would not be good.

Any suggestions?
Last edited on
kbw (9488)
Replace
map<int, string>::iterator pdiccfo;
with
map<int, string>::const_iterator pdiccfo;
rolcsar (2)
Well, this solves my problem with the print() function.
To solve the get() function I did this:

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const string& getcfo (int c) const
{
   return (diccfo.find(c))->second;
};


Has anybody a more elegant solution?

Thanks a lot!!
Last edited on
kbw (9488)
What if diccfo.find(c) returns diccfo.end()?
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