Working of a function
main
()
{
int
s;
..............
..............
..............
s
= abc(x,y,x);
.....
...
}
abc(l,k,j);
{
int
q;
......
.......
return
(q);
}
Actual
arguments:
Variables
passed as parameters to the function are called arguments
The
arguments in the call statement in the calling function are called actual
arguments. In the above program, variables ‘x’, ‘y’ and ‘z’ are actual
arguments.
Formal
arguments:
The
arguments in the declaration and definition of the function are formal
arguments. Here, variables ‘l’, ‘k’, and ‘j’ are formal arguments.
These
arguments are enclosed within the parenthesis. They must be separated by a
comma (,). These formal arguments receive values from the actual arguments.
In
the program ‘s’ receives the returned value from the function.
Function
name:
A
function name must follow the same rules as we use for identifier naming. In
fact, a function name is an identifier
Example:
sum(int a, int b);
Where,
sum() is a user-defined function and ‘a’ and ‘b’ are integer variable
arguments.
The
function call must end with a semi-colon (;).
Function
call:
A
function can be called simply using its name like other C statement, terminated
by a semi colon (;)
A
compiler executes the function, when a semi-colon (;) is en-counted after the
function name.
Return
Value:
Return
value is the outcome of the function. The result obtained by the function is
sent back to the calling function through the return statement.
The
return statement returns one value per call.
The
value returned is collected by the variable of a calling function.
There
are three ways to return a control from a called function to the point, at
which the function was invoked(called)
1.
If the function does not return a result, control is simply returned when the
function-ending right brace is reached, or by executing the statement;
return;
2.
If the function does return a result, the statement;
return
expression;
3.
returns the value of expression to the caller
Syntax of return statement
return(expression);
/*returns the value of expression to the caller */
or
return;
/*if the function does return a result the statement*/
