With VBA you can automate worksheet and chart processes and also create custom functions. Functions generated with VBA procedures are similar to the built-in functions used in worksheets. A function consists of a unique name, parentheses, and usually one or more arguments separated by a comma. A function usually returns a single value as a result. The syntax is Function Name(Arg1, Arg2,...). The number of arguments depends on the task and the use of the function. Custom functions are used from a cell in a worksheet, the same way you would use any built-in Excel function, such as SUM(Number1, Number2,...).
To create a function, you need the following:
Anyone can use the function with its name and arguments from the worksheet, but the algorithm is hidden from the user. However, a normal user is unlikely to care, as long as the function works properly.
A VBA procedure to create a function involves the following:
The part between the Function key word and the final End Function statement is called a function block. The remainder of this chapter presents a few examples to illustrate this process.
The AreaCircle() example explains the following:
By using the AreaQuad() example, you will learn the following:
The AreaSect() function serves as an example for the following:
By using the DigitSum() example, you will learn the following:
The AreaCircle1() example explains the following:
Finally, you learn how to use the Function Wizard and the Excel add-ins to create your own functions that you can use in your worksheets.