solution

Open the FigureThisOut Solution (FigureThisOut Solution.sln) file contained in the ClearlyVB2012Chap18FigureThisOut Solution folder.

a. Open the Code Editor window and study the existing code. Start the application. Click the Find a Letter button. Type the letter a and then press Enter. The btnFind_Click procedure displays the “A is in array element 0” message. Test the application using the letters b, c, and d. The procedure displays the “B is in array element 1”, “C is in array element 2”, and “D is not in the array” messages. Stop the application.

b. Change the Do clause to Do Until strLetters(intSub) = strSearchFor OrElse intSub = strLetters.Length. Save the solution and then start the application. Click the Find a Letter button. Type the letter a and then press Enter. The btnFind_Click procedure displays the “A is in array element 0” message. Test the application using the letters b and c. The procedure displays the “B is in array element 1” and “C is in array element 2” messages.

c. Click the Find a Letter button. Type letter d and then press Enter. A run time error occurs. Read the error message. Click DEBUG on the menu bar and then click Stop Debugging. Why did the modified Do clause produce a run time error?

d. Change the Do clause to Do Until intSub = strLetters.Length OrElse strLetters(intSub) = strSearchFor. Save the solution and then start and test the application to verify that it is working correctly. Close the Code Editor window and then close the solution.