teaching machines

CS 145 Lecture 9

October 7, 2011 by Chris Johnson. Filed under cs145, fall 2011, lectures.

Agenda

• compound booleans
• logical operators && and ||
• ensuring a number in a range
• stopping a command loop
• projectiles
• writing our own String.indexOf
• if/else statements

Code

LogicalFun.java

package lecture;

import java.util.Scanner;

public class LogicalFun {
  public static void main(String[] args) {
    boolean isMrRight;
    
    boolean isTall = false;
    boolean isDark = false;
    boolean isHandsome = false;
    
    boolean isRich = true;
    
    isMrRight = (isTall && isDark && isHandsome) || isRich;

    isMrRight = (isTall && isDark) ||
                (isTall && isHandsome) ||
                (isDark && isHandsome);
    
//    boolean isMrWrong = isTall && isDark && isHandsome;
//    isMrRight = !isMrWrong;
    
//    System.out.println(isMrRight);
    
    boolean isFemale = false;
    boolean isSingle = false;
    
    boolean isMrs = isFemale && !isSingle;
    boolean isMr = !isFemale;
    boolean isMs = isFemale;
    boolean isMiss = isFemale && isSingle;
    
    Scanner in = new Scanner(System.in);
    
    int number = Integer.MIN_VALUE;
    
//    while (!(number >= 0 && number <= 100)) {
    while (number < 0 || number > 100) {
      System.out.print("Enter a # in [0, 100]: ");
      number = in.nextInt();
    }
    
    in.nextLine();
    boolean wantsToLeave = false;
    
    while (!wantsToLeave) {
      System.out.print("> ");
      String command = in.nextLine();
      // TODO: go do stuff based on command
      
      // if they enter exit, quit, or logout
      wantsToLeave = command.equals("exit") || command.equals("leave") || command.equals("abandon") || command.equals("nosebleed") || command.equals("quit") || command.equals("logout");
    }
  }
}

Conditional.java

package lecture;

public class Conditional {
  
  public static int indexOf(String text, char c) {
    
    // For each letter in text...
    for () {
      // See if character is c
      // if so, we're done!
      // if not, keep on truckin'!
    }
    
  }
}

TODO

• Read sections 4.2 and 4.3.

Haiku