preprocessor directive is represented by # symbol and it include the library functions or files which are needed to do some specific task.
main function is the entry point of our code and we can compile our code withour main. in the main function,it contains several statements such as expression,declaration and return statement.
expression statements end with semicolon.
declration statemts declare a paricular variable.
return statements return value 0 which means the code is successful and has no error.
statements is basically a line of code.
