I said .... why you add parenthesis after function name ....

when we use any function generally we add parenthesis in front of it . when i ask this question to my  friend he reply " hey idiot , you dont know this easy thing "
i said can you please explain this , he said that  generally we use parenthesis for adding or supplying data to it .

I said to him , hey stop your bocus theory , now listen , if we say that we use parenthesis to any thing means it is a advantage of this thing
 ... now take another term ...
if i say that i am not supplying any data to it , than remove this parenthesis from it . then he reply that this is a syntax of it . now i am little bit agree with him

but listen to me .... and follow this url (http://javadrinks.blogspot.com/2011/08/call-c-function-without-its-name.html)every thing in memory is in form of address and divided into segements .... so ( ) is only used for fetching its segment and function_name is used for fetching its address from memory so ( ) is used for entering into function segment .