Write a program to calculate area of circle

Question

Why main function is special in C++?

Answer 1

Please study the tutorial you started for a bit - most of these questions will naturally become clearer.

Answer 2

get a grip of the maths formulas the rest will be easy.

the area of a circle can be found by multiplying pi ( π = 3.14) by the square of the radius.
If a circle has a radius of 4, its area is 3.14*4*4 quite simple maths the rest should be after getting the formula lol