Well.. the largest program that i have ever written had about 700 lines of code, but that program was to convert an integer to its English description. I could've written it with smaller lines of code but I didn't really know how to at the time.
Most of my programs consist of base and derived classes on separate files, and each file is roughly around 60 to 80 lines of code and they also consist of all the things i have learned from this website and from my c++ course in college (arrays, functions, constructors, classes, directories, strings, while loops, for loops, if statements, etc..)
So to answer your question Andy, yes i have had a go at writing a reasonable sized program with all my learned knowledge of c++
P.S Andy does this website teach ALL of the most important aspects in c++? or is there something else that is absolutely crucial for a software engineer?