1. 1 2 3 4 5 6 7 1 2 3 import becker.robots.City;
import becker.robots.Direction;
import becker.robots.RobotSE;
import becker.robots.Thing;
import becker.robots.Wall;
public class NoBrainerRobot {
public static void main(String[] args) {
City ny = new City();
Thing parcel = new Thing(ny, 1, 6);
Wall blockade1 = new Wall(ny,1,4,Direction.WEST);
Wall blockade2 = new Wall(ny,1,4,Direction.EAST);
Wall blockade3 = new Wall(ny,1,6,Direction.NORTH);
Wall blockade4 = new Wall(ny,1,6,Direction.SOUTH);
Wall blockade5 = new Wall(ny,1,6,Direction.WEST);
RobotSE mark = new RobotSE(ny, 1, 0, Direction.EAST); 1 2 3 4 5 6 7 1 2 3
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2. 1 2 3 4 5 6 7 import .... public class NoBrainerRobot {
public static void main(String[] args) {
....
mark.move(); 1 2 3 4 5 6 7
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3. Rrobot V2 Robot RobotV2 RobotSE void walkAroundToEast();
int street
int avenue
Direction direction
ThingBag backpack
void move()
void turnLeft()
void pickThing()
void putThing()
RobotV2
void walkAroundToEast();
void walkAroundToWest();
RobotSE
void turnAround();
void turnRight();
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4. import becker.robots.*; public class RobotV2 extends RobotSE {
public RobotV2(City theCity, int aStreet, int anAvenue, Direction aDirection) {
super(theCity, aStreet, anAvenue, aDirection); }
public void walkAroundToEast() {
this.turnRight(); this.move();
this.turnLeft(); this.move();
this.turnRight();
public void walkAroundToWest() {
this.turnLeft();
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5. 1 2 3 4 5 6 7 import .... public class NoBrainerRobot {
public static void main(String[] args) {
....
mark.move();
mark.walkAroundToEast();
mark.pickThing();
mark.turnAround();
mark.walkAroundToWest();
mark.putThing(); } 1 2 3 4 5 6 7
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6. Rrobot V3
RobotV2
void walkAroundToEast();
void walkAroundToWest();
RobotV3
void moveEast();
void moveWest();
If there is a blockade, then walk around; otherwise move along.
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7. Branching Statement Condition Statement Condition list 1 listF F
Statement
list 2
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8. The Syntax of if and if-else statements
A Boolean expression (logical expression). In Java, there are two possible values: true and false.
if ( condition ) {
statement list; }
Reserved words
A reserved word can’t be used as an identifier
if ( condition ) {
statement list1; }
else
statement list2;
Indentation indicates that the statements in the statement list are at the level next to the if-else statement.
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9. if – else statement Statement list 1 Statement list 1
if (Condition) { }
else
// The rest of the
// program
Statement
list 1
Condition
Statement
list 1 T
Could have another if F
Statement
list 2
Statement
list 2
The rest of the
program
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10. More services provided by Robots
int street
int avenue
Direction direction
ThingBag backbag
+Robot(City aCity, int aStreet, int anAvenue, Direction aDir)
+boolean canPickThing()
+int countThingsInBackpack()
+boolean frontIsClear()
+int getAvenue()
+Direction getDirection()
+String getLabel()
+double getSpeed()
+int getStreet() +
public #
protected -
private
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11. If there is a blockade, then walk around; otherwise move along.
import becker.robots.*;
public class RobotV3 extends RobotV2 {
public RobotV3(City theCity, int aStreet, int anAvenue, Direction aDirection) {
super(theCity, aStreet, anAvenue, aDirection); }
public void moveEast() {
if (this.frontIsClear()) {
this.move();
else {
this.walkAroundToEast();
public void moveWest() {
this.walkAroundToWest();
If there is a blockade, then walk around; otherwise move along.
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12. 1 2 3 4 5 6 7 import .... public class UsingRobotV3 {
public static void main(String[] args) {
....
RobotV3 mark = new RobotV3(ny, 1, 0, Direction.EAST);
mark.moveEast();
mark.pickThing();
mark.turnAround();
mark.moveWest(); } 1 2 3 4 5 6 7
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13. Disney Roller Coaster Ride
Measure the
kid’s height, h
h < 4 No
Yes
Ride the roller coaster
Boy or Girl?
boy
girl
Give a Mickey
Give a Mini
Next Stop
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14. Disney Ride in Java h = Integer.parseInt(
JOptionPane.showInputDialog(“How tall is the kid?”));
// IsBoy = true or false;
if (h < 4) {
if (IsBoy)// Same as if (IsBoy == true)
System.out.println(“Take a Mickey”); }
else
System.out.println(“Take a Mini.”);
} // end true part of if (h < 4)
else // else part of if (h < 4)
System.out.println(“You can ride!!”);
} // end else part of if (h < 4)
System.out.println(“Go to the next stop.”);
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15. This is still to specific!!
import ....
public class UsingRobotV3 {
public static void main(String[] args) {
....
RobotV3 mark = new RobotV3(ny, 1, 0, Direction.EAST);
mark.moveEast();
mark.pickThing();
mark.turnAround(); }
They are repeated operations 1 2 3 4 5 6 7
This is still to specific!!
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16. Loops
Condition
Statement
list T F
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17. while when there is nothing to pick Statement Condition list
while (Condition) {
Statement list }
Statement
list T F
move to next pos.
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18. 1 2 3 4 5 6 7 import .... public class UsingRobotV3 {
public static void main(String[] args) {
....
RobotV3 mark = new RobotV3(ny, 1, 0, Direction.EAST);
while (!mark.canPickThing()) {
mark.moveEast(); }
mark.pickThing();
mark.turnAround(); 1 2 3 4 5 6 7
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19. Definite Loop In programming a definite loop is more welcome.
I.e., number of iterations is known before the loop begins, at least the upper bound is known.
I.e., repeat the loop 100 times.
Precisely speaking, there is no definite loop in Java
We will talk about it in Chapter 5
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