You need a better book. This example won't work in any C++ compiler.
cin >> nCelsius >> endl;
cin >> endl will never compile. Same goes for:
//Output the results
cout << "Farenheit value is:" << endl;
cin >> nFarenheit >> endl;
which will definitely not output any result.
int nFarenheit; // 34.5 is not of type int
nFarenehit = nFactor * nCelsius/100 + 32;
Changing the type of nFarenheit to float/double is not enough if you want a floating point result.
In the division
you divide int by int which will return you an int, not a floating point number. It should be
(you could also change the type of nCelsius to float or double)
I don't see how any book, which has such errors, can teach anything properly.