CSE110 Lecture 14

Principles of Programming with Java
Loops and Conditional statements
(202005)

Transcript

1. CSE110
   Principles of Programming
   with Java
   Lecture 14:
   Loops and Conditional statements
   Javier Gonzalez-Sanchez
   javiergs@asu.edu
   javiergs.engineering.asu.edu | javiergs.com
   Office Hours: By appointment
   

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2. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 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;
   }
   }
   

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3. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 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");
   }
   

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4. Tic Tac Toe
   Case Study
   

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5. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 5
   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);
   }
   }
   

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6. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 6
   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);
   

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7. // 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);
   

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

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9. // 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);
   

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10. // 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' && h=='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' && h=='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;
    }
    

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11. // 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);
    

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12. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 12
    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);
    }
    }
    

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13. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 13
    Reference
    Chapter 3 and 4
    

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14. CSE110 - Principles of Programming
    Javier Gonzalez-Sanchez
    javiergs@asu.edu
    Summer 2020
    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.
    

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