Function is a code block that executes certain task.


Void Example

A void function doesn't return any value.



Returning Result

Via the return keyword a result can be returned.

Let's have an example in which rectangle's area is calculated by passing arguments about it's sides.



There are couple of things to mark:

  • A functions is defined at lines 13 - 16. It accepts two arguments - widthArg and heightArg both of type double.
  • The function calcRectangleArea returns a double result.
  • calcRectangleArea is called at line 9.
  • It's returned value is set in the variable area.

Common Exceptions

Return Mismatch

If a function returns value different than the specified type, it causes an exception.

In this case 5 should be replaced with string value.

Arguments Type Mismatch

Atline 12 the function expects argument of type int.

At line 9 an argument of string type is passed.

The passed argument at line 9 should be replaced with integer value.

Arguments Count Mismatch

The function calcTrapezoidArea expects 3 arguments but only 2 are passed to it.

Default Value

Default value may be specified for function parameters.

Let's look at the following:


At line 10 the function argument is not passed thus it takes the default value - 3 specified at line 13.