How To Make cin Start A New Line

I was wondering how to make cin start a new line after the semi colon. I've tried to use >> endl, << endl and \n after the variable. The code I used is:

 #include "stdafx.h"
#include "iostream"
#include "string"
using namespace std;

int main()
{
    cout << "Enter two positive numbers and this program will tell you which one is larger." << endl;
    int firstNumber, secondNumber;
    string whichIsGreater;
    cin >> firstNumber; 
    cin >> secondNumber;

    whichIsGreater = firstNumber > secondNumber ? firstNumber + " is greater." : secondNumber + "is greater.";
    cout << whichIsGreater << endl;
    return 0;
}

Hope you can give me a suggestion!

Thank you!