getting error in using sort() function

Question

please have a look at my code https://ideone.com/qk7GdO

#include <bits/stdc++.h>
using namespace std;
bool dec(const string &a,const string &b)
{
    if(a.length()!=b.length())
    return a.length()>b.length();
    return a>b;
}
int main() {
    int n,count=0;
    unordered_map<string,vector<string> >hash;
    cin>>n;
    while(n--)
    {
        string str;
        cin>>str;
        int a;
        cin>>a;
        if(hash.find(str)==hash.end())
        count++;
        while(a--)
        {
            string ns;
            cin>>ns;
            hash[str].push_back(ns);
        }
    }
    cout<<count<<endl;
    unordered_map<string,vector<string> >::iterator it;
    for(it=hash.begin();it!=hash.end();it++)
    {
        cout<<it->first;
        vector<string>v;
        for(int i=0;i<(it->second).size();i++)
        {
            string temp=(it->second)[i];
            v.push_back(temp);
        }
        sort(v.begin(),v.end(),dec);
        bool vis[v.size()];
        memset(vis,false,sizeof(vis));
        for(int i=0;i<v.size();i++)
        {
            if(!vis[i])
            {
                for(int j=i+1;j<v.size();j++)
                {
                    if(v[j]==v[i].substr(v[i].length()-v[j].length(),v[j].length()))
                    vis[j]=true;
                }
                cout<<" "<<v[i];
            }
        }
        cout<<endl;
    }


    return 0;
}

i am getting sort() function related compilation errors so it would be really great if someone could help. this is the error i am getting

error: no matching function for call to ‘sort(std::vector<std::__cxx11::basic_string<char> >::iterator, std::vector<std::__cxx11::basic_string<char> >::iterator, <unresolved overloaded function type>)’

Thanks in advance

You are not doing the function section correctly. Either use an inline function or a lambda — Jake Freeman, Dec 22 '17 at 12:47
@xtofl apparently `bits/stdc++.h` is an [internal GCC header](https://stackoverflow.com/questions/31816095/why-should-i-not-include-bits-stdc-h) which includes each and every standard header. — Quentin, Dec 22 '17 at 12:56
@xtofl Apparently, that trick is very important in "competitive programming". :/ — Baum mit Augen, Dec 22 '17 at 13:21
@JakeFreeman -- `std::sort` does not require an inline function or a lambda. It can be called with an ordinary function. The problem here is the combination of `using namespace std;` and `dec`. — Pete Becker, Dec 22 '17 at 14:44

score 1 · Answer 1 · edited Dec 22 '17 at 14:46

1

Your dec is not what you think. (http://en.cppreference.com/w/cpp/io/manip/hex)

That's the danger when you just open the std namespace.

Solutions:

remove the using namespace std; (tx @Quentin)
rename your dec to something else or
fully qualify it: sort(begin(v), end(v), ::dec)

edited Dec 22 '17 at 14:46

Pete Becker

69,019
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answered Dec 22 '17 at 12:58

xtofl

38,207
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3

Ummm... Solution: *not* spewing garbage into the global namespace by *not* `using namespace std;`? – Quentin Dec 22 '17 at 13:00
1

Well, given the infectious spread of that `using` directive it seems not :p – Quentin Dec 22 '17 at 13:01
See https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice – Raedwald Dec 22 '17 at 14:16

getting error in using sort() function

1 Answers1