Types Of Function In C Language

In C Language We Categories Function In Four Parts On The Basis Of
Their Declaration.
1)No return_type No Argument Function
2)No return_type Having Argument Function
3)Having return_type With No Argument Function
4)Having return_type With Argument Function
Now We Will See About These Type One By One With Suitable Examples
1)No return_type No Argument Function:- 
Any Function Which Are Not Returning Any Value And We Are Not Passing Any
Arguments In Function .
General Syntax For Declaration:-
  void_function_name();
*In Function Definition We Can Only Use Function_name().it means void
is optional in definition when you use windows.
Example Program:-
We Are Taking An Example Program In Which We are Printing Our Name
With the help of function.
#include<stdio.h>
void name();     //function declaration 
int main()
{
name();  //function calling
return 0;
}
void name() //function definition
{
Printf("Mantu Pathak"); //You Can give YourName .
}
The Output Of This Pogram:-
Mantu Pathak
*NOTE:-Use Void When No return_type In function declration
2)No return_type Having Argument Function:-
When Argument Is Given And Add Void Before function name then
it is know As 2) type.
General Syntax  :-
void_function_name(arg1,arg2....); //this is for declaration.
void_function_name(arg1,arg2....)  // this is for definition.
{
    function body ;
}                                  
Example Program:
We Are taking an example in which we find square root of given no.
#include<stdio.h>
void square_root(int x);
int main()
{
square_root(6);
return 0;
}
void square_root(int x)
{
int result;
result=x*x;
printf("The Square Root Of Given No Is=%d",result);
}
The Output Of This Program Is :-
The Square Root Of Given No Is=36
3)Having return_type With No Argument Function:-
in this type we can return a value without given
any argument.how can this is Done by using return keyword
AS given in below program::
Syntax For Declration and definition:-
data_type _ function_name(); //this is for declration.
data_type _ function_name() //this is for definition.
{
    function body;
}

Example Program:-
We Are taking an example in which we find square root of given no.
#include<stdio.h>
int square_root(); //function declration in this type
int main()
{
int ans;
printf("The Square Root Of Given No Is=%d",ans);
ans=square_root();
return 0;
}
int square_root()   //function definition
{
int result,a=6;
return (a*a);
}
The Output Of This Program Is:-(pic-2)
The Square Root Of Given No Is=36
4)Having return_type With Argument Function:-
In This Type We Pass Argument And return value as well.
the value is returned by using keyword return.
Syntax For Declration and definition
data_type _ function_name(arg1,arg2...); //this is for declration.
data_type _ function_name(arg1,arg2...) //this is for definition.
{
    function body;
}
Example Program:-
#include<stdio.h>
int add(int a,int b);  //declration in this method
int main()
{
int a ,b,ans;
ans=add(5,15);  //value of z copy in ans
printf("The addition is=%d",ans);
return 0;
}
int add(int x,int y)
{
int z;
z=x+y;
return (z);         //returning value of z to main function
}
The Output Of This Program Is:-
The addition is=20
                                               -:Thanks A Lot :-