CSC 112 :: Test #2 Study Guide with Answers April 25, 2012 Short Answer Questions

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1 CSC 112 :: Test #2 Study Guide with Answers April 25, 2012 Short Answer Questions (1-6) Regarding the code for Lab #7: Private Const NUMLABELS As Integer = 5 Private lblelement(numlabels) As Label ' Array of labels 1. What kind of entity is NUMLABELS? A constant of type Integer 2. What kind of entity is lblelement? An array of labels 3. What does the line Me.Controls.Add(lblElement(i)) Adds a label to the form 4. In the code for #3 above, what does Me refer to? The form itself 5. What does the line Dim somewords = My.Computer.FileSystem.ReadAllText("C:\MyWord\words.txt") Reads the entire contents of the file words.txt into the variable somewords. 6. What kind of entity is somewords? A string of characters (7-8) Regarding the code for Lab #8: 7. If our words are all of length 5, why do we divide by 7 to calculate how many words we read into the program? Because each word in the file is followed by two other characters carriage return and line feed. 1

2 8. What does Function foundin(byval ch, ByRef word) As Boolean Dim retval As Boolean = False For i = 0 To 4 If ch = word(i) Then retval = True Return retval the above function Returns True if the character ch is found in word; returns False if it is not found. (9-12) Regarding the code for Lab #9: Consider the function okindex shown below: Function okindex(byref word) As Long Dim index As Long = 0 For i = 0 To 4 index = index * 26 + (Asc(word(i)) - 65) lblindex.text = index Return index 9. If word is BEECH, what does Asc(word(0)) 65 yield? 1 because Asc( B ) = 66 & = If word is BEECH, what value does okindex return? The successive values of index are: 0 1 {for the letter B} 26*1 + 4 = 30 {for the letter E} 26* = 784 {for the letter E} 26* = {for the letter C} 26* = {for the letter H} Index returned =

3 11. What do these two lines Const raysize As Long = Dim okword(raysize) As Boolean Declare raysize as a constant with the value of and okword as a Boolean array of raysize elements. 12. In the procedure btnsetok_click what do the lines oki = okindex(word) okword(oki) = True Calculate the index of word and set that particular element of okword to True, indicating that word is in our list of words. (13-14) Regarding the code for Lab #10: 13. What do this line of code My.Computer.Audio.Play("C:\Sounds\BigBen.wav", AudioPlayMode.WaitToComplete) Causes the.wav file BigBen to play. 14. What kind of files are files with the extension.wav? Audio files (15-18) Regarding the code for Lab #11: 15. What do these lines of code Dim imagename As String imagename = txtimagename.text picshowimage.load(path + imagename) Read the name of an image file from the text box and displays that image in picshowimage. 16. Some of our files had an extension of.jpg, others an extension of.bmp. Is there a difference? Yes,.jpg files are compressed 3

4 17. Which files are lossy and which are lossless?.jpg are lossy and.bmp are lossless. 18. For the same image, are both file types of the same size with respect to storage space? No, for the same image.bmp files are much larger, but the image quality if much better. (19-18) Regarding the code for Lab #12: 19. How does the program choose a word for you to guess? Calls function Rand to get a random number between 0 and the number of words in your word file. 20. What does the procedure for btnmyguess If a letter is correct and in the right spot, turns the label blue; if a letter occurs in the word, but is in a different spot, turns the label red; otherwise turns the label green. 21. Why does our program need For i = 0 To WORDLEN - 1 chkword(i) = UCase(word(i)) the above lines of code? Because our words are all upper case. So, if we type a word using lower case, we will still find it, if our guess is correct. 22. Consider this code for function wordisok: Function wordisok(byref word) As Boolean Dim chkword(5) As String Dim indextocheck As Long For i = 0 To WORDLEN - 1 chkword(i) = UCase(word(i)) indextocheck = okindex(chkword) If indextocheck < 0 Or indextocheck > raysize Then Return False Else 4

5 Return okword(indextocheck) End If What two things does this function check for, after calculating the index of word? 1 st it checks whether the index could be the index of a 5-letter character string (with all 5 characters being alphabetic). 2 nd it looks in array okword to see if it is a word that is in our list of words. 23. If we wanted to give the player more (or fewer guesses) what change would we need to make in our program? Change the value of the constant NUMGUESSES. 24. If we wanted to add words to our dictionary what would we need to Do we have to worry about alphabetical order? Edit the file manywords.txt, but be sure all new words are in upper case letters. We can enter words anywhere in the list, regardless of alphabetical order. 25. If we wanted to use 6-letter or 7-letter words for the game, what changes would we need to make to our program? Change the value of WORDLEN and supply a list of 6- or 7- letter words. 5

NOTES: Procedures (module 15)

Computer Science 110 NAME: NOTES: Procedures (module 15) Introduction to Procedures When you use a top-down, structured program design, you take a problem, analyze it to determine what the outcome should