does all the code in C++ should be written inside main() function only....????except the class, function.....

Answer 1

main is a function. One that will be executed with highest priority (first). You can write other functions and procedures outside the main. Then you can call them from main or from each other

Answer 2

oh! now I understood thanks to you both!!!...... :-)

Answer 3

Main - it is a place where the compiler first goes to start processing.

Function-created when u are using same set of statements again and again in main block

classes- they are user defined datatypes

Answer 4

we must also remember that apart from global functions, C++ is one of the only languages which supports global variables and global constants.

So, main is mandatory for a C++ program to compile, followed by classes and functions. If there is no main, its not a C++ program, it maybe a class which could later be used in some program(s).