why main is source special or significance of main function

Answer 1

If I understand correctly, you are asking why the main function is important, and it is because every single c++ program starts from it.

Answer 2

any program most have main function and if it doesn't have it won't be start

Answer 3

main() or datatype main (), tells that the program starts from here i.e from main ()

Answer 4

@jay: main() is not a datatype. it is a function. the datatype of main function is int if it returns an int or void if it doesnt return anything