CSC161 Intro to CS in Java - Loop Worksheet 2 Answers

Answers: Loops Worksheet 2

1.   1 1     2.   6 2
     1 2          6 3
     1 3          6 4
     2 1          5 2
     2 2          5 3
     2 3          5 4
                  4 2
                  4 3
                  4 4


3.   1 3 6 10 15


4.   1
     1
     2
     2
     3
     3  1
     4
     4  2
     5
     5  3  1


5.   1  1  1

     1  2  1
     1  2  2

     1  3  1
     1  3  2
     1  3  3


     2  2  2

     2  3  2
     2  3  3



     3  3  3


6.   3  1  3
     3  1  2
     3  1  1
     3  2  3
     3  2  2
     3  3  3
     2  1  2
     2  1  1
     2  2  2
     1  1  1


7.  System.out.print("Enter a number (-999 to end): ");
    num = readin.nextInt();;
    count = 1;
    sum = 0;
    while (num != -999 && count < 5)
    {
       sum += num;
       count++;
       System.out.print("Enter a number (-999 to end): ");
       num = readin.nextInt();;
    }
    if (num != -999)
       sum += num;
    System.out.println("The sum is " << sum);


8. Enter a number (-999 to end): 10
   Enter a number (-999 to end): 20
   Enter a number (-999 to end): 30
   Enter a number (-999 to end): -999
   The sum is 60


9. Enter a number (-999 to end): 10
   Enter a number (-999 to end): 20
   Enter a number (-999 to end): 30
   Enter a number (-999 to end): 40
   Enter a number (-999 to end): 50
   The sum is 150


10. for (i = i ; i <= 9 ; i++)
    {
       for (j = 1 ; j <= i ; j++)
          System.out.print("*");
       System.out.println();
    }


11. for (i = 1 ; i <= 5 ; i++)
    {
       for (j = 1 ; j <= 5 - i ; j++)
          System.out.print(" ");
       for (j = 1 ; j <= 2*i-1 ; j++)
          System.out.print("*");
       System.out.println();
    }


12. System.out.print("Enter y or n: ");
    ans = readin.nextInt();;
    while (ans != 'y' && ans != 'n')
    {
       System.out.print("Error: please enter y or n: ");
       ans = readin.nextInt();;
    }


13. do
    {
       System.out.print("Enter y or n: ");
       ans = readin.nextInt();;
    }
    while (ans != 'y' && ans != 'n');