1. 1 DIG 3134 – Lecture 11: Two Dimensional Arrays And Dynamic Controls AND CONSTANTS Michael Moshell University of Central Florida Internet Software Design

2. 2222 The Conceptual Pathway PART ONE 2 dimensional array $Grid[$x][$y] $Miketable[$i][$j] – you can use any name, any indices This can be thought of as a Matrix of cells, like a Spreadsheet. Indices (plural of 'index') Can be numbers 1,2,3 or Strings like A, B, C. I recommend numbers, because 'for' loops are easy. 123456 1 2 3 4 5 6

3. 33333 The Conceptual Pathway PART ONE 2 dimensional array What happens if we run this code? //$mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][2]=34; } (Our convention: the first index ($i) is always “across”, the second “down”) 123456 1 2 3 4 5 6

4. 44444 The Conceptual Pathway PART ONE 2 dimensional array What happens if we run this code? //$mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][2]=34; } (Our convention: the first index ($i) is always “across”, the second “down”) 123456 1 234 3 4 5 6

5. 55555 The Conceptual Pathway PART ONE 2 dimensional array What happens if we THEN run this code? //$mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][2]=$i; } (Our convention: the first index ($i) is always “across”, the second “down”) 123456 1 2 3 4 5 6

6. 66666 The Conceptual Pathway PART ONE 2 dimensional array What happens if we THEN run this code? $mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][2]=$i; } (Our convention: the first index ($i) is always “across”, the second “down”) 123456 1 2123456 3 4 5 6

7. 77777 In-Class Exercise Modify this code to produce the second image $mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][2]=$i; } (Our convention: the first index ($i) is always “across”, the second “down”) 123456 1 2123456 3 4 5 6 123456 1 1 2 2 3 3 4 4 5 5 6 6

8. 88888 The Conceptual Pathway PART ONE 2 dimensional array What happens if we run this code? //$mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][$i]=34; } 123456 1 2 3 4 5 6

9. 99999 The Conceptual Pathway PART ONE 2 dimensional array What happens if we run this code? //$mtable[$i][$j] For ($i=1; $i<=6; $i++) { $mtable[$i][$i]=34; } 123456 134 2 3 4 5 6

10. 10 Homework #1: Due NEXT TUESDAY (ready for “gotcha” in class) Create a loop to construct this pattern in the array. (Yes, you could use two loops. But it is possible to do this with ONE loop.) I’ll take two, if you can’t figure out one. 123456 1 12 2 24 3 36 4 48 5 510 6 612

11. 11 The Conceptual Pathway PART ONE Nested LOOPs! Now it gets INTERESTINGer // $mtable[$i][$j] for ($i=1; $i<=6; $i++) { for ($j=1; $j<=6; $j++) { $mtable[$i][$j]=34; } 123456 1 2 3 4 5 6 wordpress.com What will this produce?

12. 12 The Conceptual Pathway PART ONE 2 dimensional LOOP! Now it gets INTERESTINGer // $mtable[$i][$j] for ($i=1; $i<=6; $i++) { for ($j=1; $j<=6; $j++) { $mtable[$i][$j]=34; } 123456 134 2 3 4 5 6 wordpress.com

13. 13 The Conceptual Pathway PART ONE 2 dimensional LOOP! Now it gets INTERESTINGer // $mtable[$i][$j] for ($i=1; $i<=6; $i++) { for ($j=1; $j<=6; $j++) { $mtable[$i][$j]=34; } History of $i and $j. 123456 134 2 3 4 5 6 wordpress.com $i$j 11 12 13 14 15 16 21 22 23 24 25 26 etc

14. 14 Homework #2: Modify the code so that it makes a MULTIPLICATION TABLE Like this one! // $mtable[$i][$j] for ($i=1; $i<=6; $i++) { for ($j=1; $j<=6; $j++) { $mtable[$i][$j]=?? } wordpress.com 123456 1123456 224681012 3369 1518 44812162024 551015202530 661218243036

15. 15 Now let's see shipaint.php Well, it's really just a crude PAINT PROGRAM, but it will get us started. Look at ship01.php

16. 16 The Conceptual Pathway PART ONE create a dimensional array ‘render it’ as an HTML table use to set color and size of squares HOMEWORK #3: Carefully analyze shipaint.php and be ready to EXPLAIN and HAND SIMULATE any line of code in this program.

17. 17 Goal: Build a simple Battleship Game Players take turns enter x, y, (b or g) Play the test game (shipstarter.php) Read the Requirements X  Y

18. 18 Project 3 Specification Go read the specification for Project 3 Discuss the stages from 80% to 90% Discuss the options above 90% Then we move forward to review the example code shipstarter.php is your starter kit for Project3. You may use this code as part of your submission (but you don't have to.)

19. 19 A note about $_SESSION I’m seeing lots of CONFUSED Code like $_SESSION['linenumber']=$_SESSION['linenumber']+1; in the middle of your code. I recommend: Bring in all SESSION stuff at top of main, into scalar variables like this: $linenumber=$_SESSION['linenumber']; Then in the program, as needed: $linenumber++; Put away all SESSION data at the bottom $_SESSION['linenumber’]=$linenumber;

20. 20 Upward Toward 90% Providing an Alphabetic Top Margin HINT 1: We need functions to convert 1 to A, 2 to B etc. and (to process inputs) also, A to 1, and B to 2 etc. Key Fact: There are two built-in functions in PHP to help us. $n=ord('A'); print "ASCII for 'A' is $n"; this will print ASCII for 'A' is 65

21. 21 Upward Toward 90% Two key functions: ord and chr $n=ord('A'); A  65 and $c=chr(65); 65  A

22. 22 Upward Toward 90% Providing an Alphabetic Top Margin #numtochar: maps 1 to A, 2 to B, etc. function numtochar($numin) { $numa=ord('A'); //we want numin=1 to produce chr('A'), so $numout=$numa+$numin-1; // now if numin=1, numout = chr('A') $charout=chr($numout); // and if numin=2, numout = chr('B') etc. return $charout; } #numtochar

23. 23 Upward Toward 90% Hints 2 and 3 * Go read the document "project3.hints.doc"

24. 24 The Conceptual Pathway HINT FOUR Dynamic generation of radio buttons You've seen this trick before, in the pundex program. But now, we need to do it in two dimensions. I want a bunch of radio buttons like this: … etc…. until 10.10. A total of 100 radio buttons, one fieldname.

25. 25 Dynamic radio buttons QUESTION: How can I get two pieces of information (x and y) From one radio button? ANSWER: Put the info into a string, and unpack it later. To produce this stuff: … Here's the trick - put this in your drawgrid 2d loop - print " ";

26. 26 Unpacking the info QUESTION: How can I get two pieces of information (x and y) From one string like 1.2? ANSWER: Bang! - - explode it. $f=$_POST['fillhere']; // (why $f? why the $f not!!?) // (I just like f for 'fillhere') If ($f) { $fparts=explode('.',$f); $x=$fparts[0]; $y=$fparts[1]; } // now you can do $Grid[$x][$y]=whatever color

27. 27 And Finally... QUESTION: What's WHITE? BLUE? LIGHTBLUE? These are Defined Colors in HTML (147 of ‘em!) www.w3schools.com/html/html_colornames.asp But... how can they be passing through to the browser WITH NO QUOTES AROUND ‘EM? $Ships[$x][$y]=GOLD; It’s an Ancient Flaw in PHP. ‘twould be better as: $Ships[$x][$y]=‘GOLD’; // straight quotes of course

28. 28 And Then.... QUESTION: What do we do next? 1)The practice (homework) problems, for next week 2)Start building Project 3. It’s due on 8 November (for show-and-tell); 10 November for grading. AND if you have less than 150 on the MIDTERM, You need to undergo the Remedial Process to salvage your grade. See Prof for Details. Limited Time Offer.