C + + Programming to Convert Temperature

# include <iostream>
# include <string>


using namespace std;
int main ()
{
    int K;
    int R;
    int C;
    int F;


    cout << "Showing Temperature Convertion" << endl;
    cout << "Enter the large temperature (C):";
    cout << endl;
    cin >> C;
    R = 4/5 * C;
    F = 9/5 * C +32;
    K = C +273;
  
    cout << "Convertion to Reamur =" << R << endl;
    cout << "Convertion to Fahrenheit =" << F << endl;
    cout << "Conversion to Kelvin =" << K << endl;
  
    system ("pause");
    return 0;
}