preprocessor directive - It is run before the compiler and it is used to include other files in the code like some header files and here we are including iostream.h which is a header file which contains the input output library.
Main function - It is the function from where the program starts to run.
Expression statement - The statement which have expression along with semi colon in the end are called Expression statement.
Declaration statement - These statement are used to declare something like variable, constant and so on.
Return statement - It is used to return the value of the function or some special code in main function like 0 if there is no problem in the program or it will return some other values.
