47.Returning a value to the calling function

 

Returning a value to the calling function:

We can send data from calling function to the called by function using arguments or parameters.

The called by function is capable to send back a single value to the calling function.

"return" is a statement used to return a single vale to the calling function.

"return" statement is also used to terminate the execution of a function.

 

Example:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output:

Sum=50

 

Example explained:

The values of x, y (actual arguments) are assigned to p, q (formal arguments).

Sum of two numbers (r) is returned to calling function and assigned to "z".

Value of "z" (50) is printed as sum.

 

Working with other types (other than integers):

By default C compiler considers arguments and return value as integers.

If we use other types as arguments and return value then function declaration and return type must be specified otherwise it results error.

 

Example:

#include<stdio.h>

void main()

{

float x,y,z;

clrscr();

x=12.45;

y=25.15;

z=adding(x,y);

printf("Sum=%f",z);

getch();

}

adding(float p,float q)

{

    float r;

    r=p+q;

    return r;

}

 

Output:

Error: Floating point error: Domain

 

Example explained:

By default C compiler considers arguments and return type as integers.

It has given error because arguments and return value are of floating point types.

We can rectify the program by specifying the return type and declaration.

 

Example rectified:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output:

Sum=37.599998

 

 

 

 

Putting all together:

Function is a self-contained block of code that performs a particular task.

It helps to follow modular approach in developing applications.

It helps to reduce development time.

It promotes reusability.

Defining and using of any function required three things.

1. Function definition.
2. Function calling statement.
3. Function declaration.

Function definition:

Any function has a name which must be a valid identifier.

List of formal arguments are defined, the values of which are assigned by the actual arguments of calling statement.

Body of the function is defined with in { }

"return" is the statement used to return maximum a single value to the calling function.

"return" is also used to terminate the execution of a function.

Return type is specified if the function returns a non-integer. At least void must be specified if a function doesn't return any value.

Syntax:   <return type> <name>( <List of formal arguments> )   {      ----------------      ----------------      return <exp>;      ----------------      ----------------   }   Example:          int   adding(int  x, int  y)        {              return x+y;        }                  (or)          int   adding(x,y)        int x,y;        {              return x+y;        }