ME 142 Engineering Computation I Input, Output & Documentation

Key Concepts Documentation Getting Program Input and Returning Program Output Linking a Program to a Button

Header Example ‘Purpose: ‘This program computes the hypotenuse of a ‘triangle, given the legs ‘Input: ‘A, B – legs of the triangle ‘Output: ‘Hyp – hypotenuse of the triangle ‘Author: GS Miller ‘Date Created: 10/15/2008 ‘Limitations: None

Improving Program Readability  Include Header  Use descriptive variable names  Use indentation and blank lines to clarify structure  Add other comments as appropriate

Getting Input/Returning Output  Via Functions Passing Information to a Function via an Argument List Returning Results from a Function to a Cell  Direct to/from a Spreadsheet Reading Data from a Spreadsheet Cell Returning Data to a Cell  Dialog Boxes InputBox Function MsgBox Function

Getting Input/Returning Output  VBA Supports 2 types of programs Functions Subprograms or Subroutines  Functions typically receive all of their input through the parameter list and write their output to the cell from which the function was launched  Subprograms may read/write directly to/from cells Sub MyPgm() … End Sub

Using the Cells command to Read/Write Spreadsheet Data  Data may be read from a spreadsheet cell using the cells command as shown below: variable = Cells(row,col) row,column – the address of the cell to be read variable – name of variable which receives the contents of the cell

Using the Cells command to Read/Write Spreadsheet Data  Data may be written to a spreadsheet cell using the cells command as shown below: Cells(row,col) = variable row,column - the address of the cell to be written variable – variable to be written to the cell

Using the Cells command to Read/Write Spreadsheet Data  Example: Sub Square() A=cells(2,1) B=A^2 cells(2,2)=B End Sub

Linking a Program to a Button

InputBox Function  Used to obtain a single value from the user MyVar = InputBox(prompt [, title] [,default]) Where Prompt – is the text displayed in the input box (required) Title – text displayed in the input box’s title bar (optional) Default – defines the default value (optional) MyVar – variable which will receive the input entered

InputBox Function  Examples Name = InputBox("Please enter your name: ","Name") MyNum = Val(InputBox("Enter the height:", "Height"))

MsgBox Function  Used to display information and get simple user input [MyVar =] MsgBox(prompt [, buttons] [,title]) Where Prompt – is the text displayed in the message box (required) Buttons – specifies buttons/icons appear in the message box (optional) Title – specifies the text displayed in the input box’s title bar (optional) MyVar – variable receiving value of mouse click button (optional)

MsgBox Function  Examples Ans = MsgBox("Continue processing?", vbYesNo) MsgBox "Click OK to begin printing"

Common MsgBox Function Constants Constant NameEnd Result vbOKOnly vbOKCancel vbAbortRetryIgnore vbYesNoCancel vbYesNo vbRetryCancel Displays OK Button only Displays OK and Cancel buttons Displays Abort, Retry, and Ignore buttons Displays Yes, No, and Cancel buttons Displays Yes and No buttons Displays Retry and Cancel buttons