Finding value in unordered_map

Question

I am using Boost unordered_map. I have a key value pair for each entry. How could I determine whether a particular value exist in the map? (I don\'t want to create another u

Answer 1

Why can't we use count method instead of find()

Description: Count elements with a specific key Searches the container for elements whose key is k and returns the number of elements found. Because unordered_map containers do not allow for duplicate keys, this means that the function actually returns 1 if an element with that key exists in the container, and zero otherwise.

unordered_map hash;
    //converted array into hashMap
    for(int i=0; i<6; i++)
    {
        hash[i];
    }

    //commom elemenest value is set to 1 in hashMap
    for(int i =0; i<7; i++)
    {
        //element exist in array1
        if(hash.count(i))
        {
            hash[i] = 1;
        }
    }