This document contains lecture slides for CSE110 Principles of Programming with Java. It discusses loops and conditional statements like break, continue, and nested loops. It then presents a case study on implementing Tic Tac Toe in Java, with pseudocode showing how to initialize the game board, take user and computer moves, check for a winner or tie, and reprint the board. The slides are attributed to instructor Javier Gonzalez-Sanchez and provide his contact information.

1. CSE110
Principles of Programming
with Java
Lecture 13:
Loops and Conditional statements
Javier Gonzalez-Sanchez
javiergs@asu.edu
javiergs.engineering.asu.edu
Office Hours: By appointment

2. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 2
break Statement
• We can use a “break” statement to get out of the
loop
for (int i=1; i<=100; i=i+2) {
System.out.println(i);
if (i % 15 == 0) {
break;
}
}

3. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 3
continue Statement
• After executing a continue statement, the rest of
the statements within the loop will be skipped, then
the loop condition will be evaluated again.
for (int i=1; i<=4; i+=1) {
System.out.println(i);
System.out.println("Before");
if (i % 2 == 0) {
continue;
}
System.out.println("After");
}

4. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 4
Nested loops
• We can have a loop inside of another loop
for (int i=1; i<=3; i=i+1) {
for (int j=4; j>=1; j=j-1) {
System.out.println(i + "," + j);
}
}

5. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 5
One more thing
• We can have a loop inside of another loop
for (int i=1; i<=3; i++) {
for (int j=4; j>=1; j--) {
System.out.println(i + "," + j);
}
}

6. Tic Tac Toe
Case Study

7. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 7
TicTacToe.java
import javax.swing.*;
public class TicTacToe {
public static void main(String [] args) {
// 1. initialize
do {
// 2. user move
// 3. continue?
// 4. computer move
// 5. winner or tie?
// 6. print
} while (true);
}
}

8. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 8
TicTacToe.java
// 1. initialize
char a = ' ', b = ' ', c = ' ';
char d = ' ', e = ' ', f = ' ';
char g = ' ', h = ' ', i = ' ';
System.out.println("Game: ");
System.out.println(" " + a + " | " + b + " | " + c);
System.out.println("----------");
System.out.println(" " + d + " | " + e + " | " + f);
System.out.println("----------");
System.out.println(" " + g + " | " + h + " | " + i);

9. // 2. user move
boolean userFail;
do {
String option = JOptionPane.showInputDialog("Player:");
int move = Integer.parseInt(option);
userFail = true;
switch (move) {
case 1: if (a == ' ') {a = 'X'; userFail = false;} break;
case 2: if (b == ' ') {b = 'X'; userFail = false;} break;
case 3: if (c == ' ') {c = 'X'; userFail = false;} break;
case 4: if (d == ' ') {d = 'X'; userFail = false;} break;
case 5: if (e == ' ') {e = 'X'; userFail = false;} break;
case 6: if (f == ' ') {f = 'X'; userFail = false;} break;
case 7: if (g == ' ') {g = 'X'; userFail = false;} break;
case 8: if (h == ' ') {h = 'X'; userFail = false;} break;
case 9: if (i == ' ') {i = 'X'; userFail = false;} break;
default: userFail = true;
}
} while (userFail == true);

10. // 3. continue?
if (a!=' ' && b!=' ' && c!=' ' &&
d!=' ' && e!=' ' && f!=' ' &&
g!=' ' && h!=' ' && i!=' ') break;

11. // 4. computer move
boolean computerFail = false;
do {
double x = Math.random();
double y = Math.random();
if (x <= 0.33) {
if (y <= 0.33) {
if (a == ' '){a = 'O'; computerFail = false;} else {computerFail = true;}
} else if (y > 0.33 && y < 0.66) {
if (b == ' ') {b = 'O'; computerFail = false;} else {computerFail = true;}
} else if (y >= 0.66) {
if (c == ' ') {c = 'O'; computerFail = false;} else {computerFail = true;}
}
} else if (x > 0.33 && x < 0.66) {
if (y <= 0.33) {
if (d == ' ') {d = 'O'; computerFail = false;} else {computerFail = true;}
} else if (y > 0.33 && y < 0.66) {
if (e == ' ') {e = 'O'; computerFail = false;} else {computerFail = true;}
} else if (y >= 0.66) {
if (f == ' ') {f = 'O'; computerFail = false;} else {computerFail = true;}
}
} else if (x >= 0.66) {
if (y <= 0.33) {
if (g == ' ') {g = 'O'; computerFail = false;} else {computerFail = true;}
} else if (y > 0.33 && y < 0.66) {
if (h == ' ') {h = 'O'; computerFail = false;} else {computerFail = true;}
} else if (y >= 0.66) {
if (i == ' ') {i = 'O'; computerFail = false;} else {computerFail = true;}
}
}
} while (computerFail == true);

12. // 5. a winner or tie?
if (a=='O' && b=='O' && c=='O' ||
d=='O' && e=='O' && f=='O' ||
g=='O' && h=='O' && i=='O' ||
a=='O' && d=='O' && g=='O' ||
b=='O' && e=='O' && f=='O' ||
c=='O' && f=='O' && i=='O' ||
a=='O' && e=='O' && i=='O' ||
c=='O' && e=='O' && g=='O' ) {
System.out.println("YOU LOST!");
break;
} else if (a=='X' && b=='X' && c=='X' ||
d=='X' && e=='X' && f=='X' ||
g=='X' && h=='X' && i=='X' ||
a=='X' && d=='X' && g=='X' ||
b=='X' && e=='X' && f=='X' ||
c=='X' && f=='X' && i=='X' ||
a=='X' && e=='X' && i=='X' ||
c=='X' && e=='X' && g=='X' ) {
System.out.println("You Win!");
break;
} else if (a!=' ' && b!=' ' && c!=' ' &&
d!=' ' && e!=' ' && f!=' ' &&
g!=' ' && h!=' ' && i!=' ') {
System.out.println("It is a tie");
break;
}

13. // 6. print
System.out.println("Game: ");
System.out.println(" " + a + " | " + b + " | " + c);
System.out.println("----------");
System.out.println(" " + d + " | " + e + " | " + f);
System.out.println("----------");
System.out.println(" " + g + " | " + h + " | " + i);

14. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 14
TicTacToe.java
import javax.swing.*;
public class TicTacToe.java {
public static void main(String [] args) {
// 1. initialize
do {
// 2. user move
// 3. continue?
// 4. computer move
// 5. winner or tie?
// 6. print
} while (true);
}
}

15. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 15
Reference
Chapter 3 and 4

16. CSE110 - Principles of Programming
Javier Gonzalez-Sanchez
javiergs@asu.edu
Summer 2017
Disclaimer. These slides can only be used as study material for the class CSE110 at ASU. They cannot be distributed or used for another purpose.