Google + Content reposting May 4 2015

Digital and Interactive Games 2015, Term 2, Session 2
Bitwise Operations
Queue

& - and
| - or
XOR – xor
! - not


P    q    AND    OR    XOR    NOT     
0    0    0    0    1         
0    1    0    1    0         
1    0    0    1    0         
1    1    1    1    1      

http://i483.photobucket.com/albums/rr193/Brenorenz/W10S003_zpshaut6ljy.png

Ex
Bit 7 – 1 indicates the top of the door
Bit 3 – 0 indicates the bottom of the door
–    left hinge
top/bottom, left/right hinge

http://i483.photobucket.com/albums/rr193/Brenorenz/W10S004_zpsdv2cwffu.png

int topLeft = 0; 10001000
0000 0000 0000 0000
MSB           LSB
topLeft = 128 + 8; // set bit 7 and 3 on.


// check if bit 7 is on
if (topLeft & 128 == 128)

Shift left 10001000
    --------------
       00010000
---
char ch;

for (int i = 0; i < 10; i++) {
    ch = (char) ('x' + i);
    System.out.print(ch);
  
    ch = (char) ((int) ch OR 65503);
    System.out.print(ch);
}


1 1 1 1  1 1 1 1   1 0 1 1  1 1 1 1


char aDoor;

// bit 7 - top part of the door
//    - bottom part of the door
// bit 3 – 1 – left hinge
//


aDoor = 0;
aDoor = (char) ((int) aDoor | 128);
aDoor = (char) ((int) aDoor | 8);


Turn on - all to zero except the target bit, then OR it.
i.e. turn bit 3 on.
    Var | 00001000


Turn off – all to one except target bit, then AND it.
i.e. turn bit 6 off
    var & 10111111


Textbook Ch 5.

System.out.print(aDoor);
System.out.print(int) aDoor & (256 – 8);
System.out.print(int) aDoor;

// Turn it back on
aDoor = (char) ((int) aDoor | 8);

System.out.println();

// Shift 1 bit
aDoor = (char) ((int) aDoor << 1);
System.out.print((int) a Door);
System.out.print(ol);


aDoor = (char) ((int) aDoor >> 2);
System.out.print((int aDoor);


Queue

<a href="http://s483.photobucket.com/user/Brenorenz/media/W10S005_zpsyxnsfo3h.png.html" target="_blank"><img src="http://i483.photobucket.com/albums/rr193/Brenorenz/W10S005_zpsyxnsfo3h.png" border="0" alt=" photo W10S005_zpsyxnsfo3h.png"/></a>
http://i483.photobucket.com/albums/rr193/Brenorenz/W10S005_zpsyxnsfo3h.png

remove + 20 is at position 0.


property: MAX_ITEMS
      : item[] int
      : begin int
      : end int
      : count int


Method : Add
       Remove
       get MaxItems : int
       getCount
       Search (int) : int

http://i483.photobucket.com/albums/rr193/Brenorenz/W10S006_zpsda3c68xm.png

INVALID
–    99999

Que Sample
Queue
public class Queue {
    private int MAX_ITEMS = 20;
    private int count = 0;
    private int begin = 0;
    private int end = 0;
    private int INVALID = 99999;

    public void print() {

    }

    public boolean add(int value) {
        boolean result = false;
        if (count < MAX_ITEMS) {
            item[end] = value;
            ++end;
            result = true;
        }
        ++ count;
        return result;
    }

    public int getMaxItems() {
        return MAX_ITEMS;
    }

    public int getCount() {
        return count;
    }


…

Test cases
Overall scenarios
–    working
–    expected errors

(1)    Add an item to an empty queue
Values: 5, 10, 0, -20
Expected : B : MaxItem = 2    count = 0    peek = 99999
    A : MaxItem = 2    count = 0    peek = 99999
print →


B : MaxItem = 20    count = 1    peek = 5
A : MaxItem = 20    count = 1    peek = 5
print


(2)
    Add 20 items
    Then add 1 item

    B:
    print
    A: print


Stack

http://i483.photobucket.com/albums/rr193/Brenorenz/W10S007_zpssjrbmotw.png

Queue.java (part of)
public class Queue {
    private int MAX_ITEMS = 20;
    private int count = 0;
    private int item[] = new int{MAX_ITEMS];
    private int begin = 0;
    private int end = 0;
    private int INVALID = 99999;


    int index = begin;
    for (int i=0; i< count; ++i) {
        System.out.print[index] + “ ”);
        ++index;
        if (index == this.MAX_ITEMS) {
            index = 0;
        }
    }
}


…
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