Because the number of terms must be at least 3, otherwise we exit the program entirely. We output the first two terms 'manually' instead of using the loop because these two terms are "automatically" set.
The code is available here: github.com/portfoliocourses/cplusplus-example-code/blob/main/fibonacci.cpp. If you run it, and enter in 100, it should give you the first 100 terms. :-)