problems using multimap in c++

Question

vector<vector<string>> groupAnagrams(vector<string>& s) { vector<vector<string>> res; multimap<string,int> m; vector<string>::iterator it; for(it=s.begin();it!=s.end();it++){ sort((*it).begin(),(*it).end()); } int i=0; for(it=s.begin();it!=s.end();it++){ m.insert(pair<string,int>(*(it),i)); i++; } //sort each string multimap<string,int>::iterator it; sort(m.begin(),m.end()); //sort all strings string st=s[0]; for(it=m.begin();it<m.end();it++){ vector<string> temp; temp.push_back(s); if((*it)->first == st){ temp.push_back((*it)->first); } res.push_back(temp); if((*it)->first != st){ st=(*it)->first; } } return res; }

The code is for grouping anagrams. I used multimap for mapping the word to the initial index. sorted the individual word first and then sorted the entire set of words.The error i'm getting is

conflicting declaration ‘std::multimap<std::basic_string<char>, int>::iterator it’

you already have a variable called it (vector<string>::iterator it; ). Call your multimap iterator something else... — StevieG
– StevieG, Commented Aug 13, 2015 at 13:47
You could rename one of the two things you named it as the earlier comment and answers suggest. But it is better style to limit the scope of each use of it rather than vary the name. for(auto it=m.begin();it<m.end();it++) or for(multimap<string,int>::iterator it=m.begin();it<m.end();it++) instead of declaring it seperately before use. — JSF
– JSF, Commented Aug 13, 2015 at 13:50
That's not the only error you're getting, and not even the full error. The compiler tells you which line it's on, and also says previous declaration as ‘std::vector<std::basic_string<char> >::iterator it’ and tells you which line that previous declaration is on. So in short, just read the error messages properly. — Jonathan Wakely
– Jonathan Wakely, Commented Aug 13, 2015 at 13:55

Brandon · Accepted Answer · 2015-08-13 13:46:31Z

2

You are declaring the same variable (it) twice with different types. Use a different variable name for one of the declarations.

answered Aug 13, 2015 at 13:46

Brandon

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Comments

NathanOliver · Accepted Answer · 2015-08-13 13:47:25Z

You have declared it twice. first vector<string>::iterator it; and then with multimap<string,int>::iterator it;. You will need to rename one of them.

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