sample_map.cpp

#include <iostream>
#include <algorithm>
#include <string>
#include <map>

using namespace std;

int main() 
{
    unsigned long totalQuery = 0;
    unsigned int query = 0;
    string name("");
    map<string, unsigned int> scoreContainer = {};
    unsigned int score = 0;
    
    cin >> totalQuery;
    
    if (!((totalQuery >= 1) && (totalQuery <= 100000) ))
    {
        return 0;    
    }
    
    for (auto count = static_cast<unsigned long>(0); count < totalQuery ; ++count)
    {
        cin >> query;
        cin >> name;
        cin >> score;
        
        if ( !( (query >= 1 && query <= 3) && (name != "") && (score >= 1 && score <= 1000)) )
        {
            return 0;    
        }
        
        switch(query)
        {
            case 1:
            {
                auto it = scoreContainer.find(name);
                if (it != scoreContainer.end())
                {
                    it->second += score;
                }
                else
                {
                    scoreContainer[name] = score;
                }
            }
            break;
            case 2:
            {
                auto it = scoreContainer.find(name);
                if (it != scoreContainer.end())
                {
                    scoreContainer.erase(it);
                }
            }            
            break;
            case 3:
            {
                auto it = scoreContainer.find(name);
                if (it != scoreContainer.end())
                {
                    cout << it->second << endl;
                }
                else
                {
                    cout << 0 << endl;
                }
            }                    
            break;
        }
        
        name.clear();
    }
    
    return 0;
}

Sample C++ example to illustrate the usage of map with auto keyword.