C ++：没有匹配的函数来调用

Question

Sorry for my English.

I defined my own function that compare two maps ( if the input includes the word ) . The problem is , when i use it in the anagram function , i have the error " no matching function for call to compare maps " . I think it's a problem with my arguments , more precisely with iter . here is my function :

bool comparemaps(std::map<char, int>::iterator  wordfirst , std::map<char, int>::iterator  wordlast , std::map<char, int>::iterator  inputfirst , std::map<char, int>::iterator  inputlast){

map<char, int>::const_iterator w = wordfirst , i=inputlast;

while(w != wordlast){

    if(i == inputlast || w->first < i->first)
        return false;

    if(w->first == i->first){

        if(w->second > i->second)
            return false;

        else
            w++;
            i++;
        }

    if(w->first > i->first)
        i++;


    }
return true;
}

and in the anagram function (not finished):

vector<vector<string> > anagrams(const string& input , const Dictionary& dict ,
                             int max){

map<char,int>  inputmap;

fillmap(inputmap, input.begin(),input.end());

for( Dictionary::const_iterator iter = dict.begin(); iter != dict.end() ; iter++){


    comparemaps(iter->letters.begin(),iter->letters.end(), inputmap.begin(), inputmap.end());


       }

i think it's a problem with iter->letters.begin() and iter->letters.end() . letters is a map in a structure named word . Dictionary is a vector of word . the header is defined like this ( in hpp file ) :

bool comparemaps(std::map<char, int>::iterator  wordbegin , std::map<char, int>::iterator  wordlast , std::map<char, int>::iterator  inputbegin , std::map<char, int>::iterator  inputlast);

i'm asking for help ! tell me if you want more information

Answer 1

Assuming Dictionary is defined as:

typedef std::vector<Word> Dictionary;

and Word is defined as:

struct Word
{
    map<char,int> letters;
};

then:

Dictionary::const_iterator iter

points to const Word , which implies that iter->letters.begin() returns map<char,int>::const_iterator which is not convertible to map<char,int>::iterator required by your function comparemaps .

Change the signature of your function into:

bool comparemaps(std::map<char, int>::const_iterator  wordfirst
               , std::map<char, int>::const_iterator  wordlast
               , std::map<char, int>::iterator  inputfirst
               , std::map<char, int>::iterator  inputlast);