C++ Map Iterator

Question

The program just prints the most repeated word. How can I make it if there is no most repeated word to print error or "none"?

Input: 5 apple apple

Answer 1

Your use of std::max_element() is returning an iterator to the first element with the largest second value.

You can then use std::any_of() or std::none_of() to check if there are any remaining elements that have the same second value:

auto iter = max_element(begin(freq), end(freq), [](const mmap::value_type& a, const mmap::value_type& b) { return a.second < b.second; }); 
if ((iter == end(freq)) || any_of(next(iter), end(freq), [&](const mmap::value_type& a){ return a.second == iter->second; }))
    cout << "none";
else
    cout << iter->first;

Live demo

auto iter = max_element(begin(freq), end(freq), [](const mmap::value_type& a, const mmap::value_type& b) { return a.second < b.second; }); 
if ((iter != end(freq)) && none_of(next(iter), end(freq), [&](const mmap::value_type& a){ return a.second == iter->second; }))
    cout << iter->first;
else
    cout << "none";

Live demo