#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <cassert>
using namespace std;
/*Write the class AddElements here*/
template <typename T>
class AddElements
{
    
public:
    T element;

    AddElements(const T& element)
        :
        element(element)
        {}

    T add(const T& other) 
    {
        return this->element + other;
    }

    T concatenate(const T& other) 
    {
        return this->element + other;
    }
};

int main () {
  int n,i;
  cin >> n;
  for(i=0;i<n;i++) {
    string type;
    cin >> type;
    if(type=="float") {
        double element1,element2;
        cin >> element1 >> element2;
        AddElements<double> myfloat (element1);
        cout << myfloat.add(element2) << endl;
    }
    else if(type == "int") {
        int element1, element2;
        cin >> element1 >> element2;
        AddElements<int> myint (element1);
        cout << myint.add(element2) << endl;
    }
    else if(type == "string") {
        string element1, element2;
        cin >> element1 >> element2;
        AddElements<string> mystring (element1);
        cout << mystring.concatenate(element2) << endl;
    }
  }
  return 0;
}

Templates Go Further

1. Explicit(full) template Specialization