Homework 3

Part A

Answer the following in a Word or .txt document. Attach this to the same submission as for part B

Describe a specific situation where a while loop would make more sense than a for loop, and a specific situation where a for loop would make more sense than a while loop. "Specific situation" means: make up a program scenario; you may not use any scenario already used in a classwork, homework, or lecture example.
Explain why we would want to use a sentinel value. When can we not use a sentinel value?

Part B

We will use Java to do a few programming tasks. Here is an online Java IDE -- an editor that also lets you run code right in the browser. Make a new .java file

More about using the IDE for this course.

The following example code shows using loops in java.

// This code sets things up for a general java program with input
import java.util.Scanner;
public class Main
{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
// done with setup, main code starts here   

        String secretWord = "swordfish";
        
        // print and then read in a String from the user
        System.out.println("Guess the word?");
        String user = scan.next(); 
        
        // while the user's word is not the same as the secret
        // note .equals() for checking string equality in java
        while (! user.equals(secretWord)) {
             System.out.println("Wrong! Try Again");
             user = scan.next(); 
        }
        
        System.out.println("You got it right!");
        
        
        // a for loop to print numbers from 0 to 9
        for (int i = 0; i < 10; i++) {
          System.out.println(i);
        }
        
        // nested for loops to print a grid of X's
        for (int i = 0; i < 3; i++) {
          for (int j = 0; j < 4; j++) {
             System.out.print("X"); // print continues on the same line
          }
          System.out.println(); // println moves to a new line
        }
            
        

// main code ends (still need the below two lines!!)  
    }
}

Do each in its own program:

Test the users on their squares knowledge from 1*1 to 9*9 -- for each number from 1 to 9, ask the user for its square, and make them keep trying to guess it until they get it right, then congratulate them for getting it right.
Print a table of sums from 1+1 to 5+5 using one nested loop structure.
[EC +10] Also print headers on the rows and columns. The top header can be done in a separate loop. It might look like
```
---1---2---3---4---5
1| 2   3   4   5   6   
2| 3   4   5   6   7   
3| 4   5   6   7   8   
4| 5   6   7   8   9   
5| 6   7   8   9   10  
```