The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference, 2nd Edition
by Nicolai M. Josuttis, Addison Wesley Longman, 2012
Copyright © 2012 by Pearson Education, Inc. and Nicolai M. Josuttis
#include <ratio>
#include <iostream>
using namespace std;
int main()
{
typedef ratio<5,3> FiveThirds;
cout << FiveThirds::num << "/" << FiveThirds::den << endl;
typedef ratio<25,15> AlsoFiveThirds;
cout << AlsoFiveThirds::num << "/" << AlsoFiveThirds::den << endl;
ratio<42,42> one;
cout << one.num << "/" << one.den << endl;
ratio<0> zero;
cout << zero.num << "/" << zero.den << endl;
typedef ratio<7,-3> Neg;
cout << Neg::num << "/" << Neg::den << endl;
}