Solutions to the Try It Out Exercises in Java For Dummies, 8th Edition
by Barry Burd

Chapter 6: Controlling Program Flow with Loops

In this chapter:

• Bigger and Better
• No Negativity
• For Amour
• Collecting Values
• Factorial
• Seeing Stars
• Seeing More and More Stars
• Three Triangles
• Missed Opportunity
• Let's Bust Out of Here
• Carry On and Keep Coding

Bigger and Better

import static java.lang.System.out;
import java.util.Scanner;
import java.util.Random;

public class GuessAgain {

    public static void main(String[] args) {
        var keyboard = new Scanner(System.in);

        int numGuesses = 0;
        int randomNumber = new Random().nextInt(100) + 1;

        out.println("       ************         ");
        out.println("Welcome to the Guessing Game");
        out.println("       ************         ");
        out.println();

        out.print("Enter an int from 1 to 100: ");
        int inputNumber = keyboard.nextInt();
        numGuesses++;

        while (inputNumber != randomNumber) {
            out.println();
            if (inputNumber < randomNumber) {
              out.println("Try again with a higher number ...");
            } else {
              out.println("Try again with a lower number ...");
            }
            out.print("Enter an int from 1 to 100: ");
            inputNumber = keyboard.nextInt();
            numGuesses++;
        }

        out.print("You win after ");
        out.println(numGuesses + " guesses.");

        keyboard.close();
    }
}

No Negativity

import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    var keyboard = new Scanner(System.in);
    System.out.print("Enter a number (non-positive to quit): ");
    int number = keyboard.nextInt();

    int largest = number;

    while (number > 0) {
      if (number > largest) {
        largest = number;
      }
      System.out.print("Enter a number (non-positive to quit): ");
      number = keyboard.nextInt();
    }

    if (largest > 0) {
      System.out.println("The largest is " + largest);
    } else {
      System.out.println("You didn't enter any positive numbers.");
    }
    keyboard.close();
  }

}

For Amour

jshell> import static java.lang.System.out

jshell> for (int i = 0, j = 10; i < j; i++, j--) {out.println(i + " " + j);}
0 10
1 9
2 8
3 7
4 6

Collecting Values

45

Factorial

import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    var keyboard = new Scanner(System.in);
    System.out.print("Enter an integer: ");
    int n = keyboard.nextInt();

    int factorial = 1;
    for (int i = 1; i <= n; i++) {
      factorial *= i;
    }

    System.out.println(n + "! is " + factorial);
    keyboard.close();
  }
}

Seeing Stars

*****
*****
*****
*****
*****

Seeing More and More Stars

*
**
***
****
*****

Three Triangles

public class Snippet {

  public static void main(String[] args) {

    for (int copy = 0; copy < 3; copy++) {
      for (int row = 0; row < 5; row++) {
        for (int column = 0; column <= 4 - row; column++) {
          System.out.print("*");
        }
        System.out.println();
      }
    }

  }
}

Missed Opportunity

Enter an int from 1 to 10: 7

Try again...
Enter an int from 1 to 10: 7
You win after 2 guesses.

Let's Bust Out of Here

Enter an int value: 5
5
Enter an int value: 3
3
Enter an int value: -6
-6
Enter an int value: 0
Done!

Carry On and Keep Coding

Enter an int value: 100
Enter an int value: 500
Enter an int value: 9
9
Enter an int value: -1
-1
Enter an int value: 0
Done!