If you actually want to use and test your circle class, you will need a main function which you will compile to use with it. This program is often known as a driver program. As an example, for testing ...

The biggest program with C++ is the quality of program is so poor. Perhaps thats due to the programmer, perhaps the language. If I look at C code I can easily assess it easily.

You can use C++ without using object-oriented programming. ... C++ provides tools for avoiding them. E.g. using a string class will ensure your string buffer is never 1 byte too short.

C++’s origins date back to 1979, when Bjarne Stroustrup, the programming language’s creator, first began work on the language that was then known as “C with Classes”.