structure of the c rogram

Every c program consists of one or more modules called functions.One of the functions must be called main.The programing will always begin by executing the main function.Any other function definition must be defined separately,either ahead or after the main.each function must contain :
                                                                  

1.  A function heading,which consists of function name followed by an optional list of arguments,enclosed in parantheses.
2. a list of argument declarations,if arguments are included in the heading.
3. a compound statement,which comprises the remainder of the function.