CSC161 Intro to CS in Java

Loop Worksheet

Show the output produced by the following segments of code. Assume that
all variables are declared as int.


1.  i = 2;                       2.  i = 2;
    while (i <= 15)                  sum = 0;
    {                                while (i <= 15)
       System.out.println(i);        {
       i = i + 2;                       sum = sum + i;
    }                                   i = i + 2;
                                     }
                                     System.out.println(sum);


3.  i = 40;                      4.  i = 40;
    j = 10;                          j = 10;
    while (i > j)                    while (i > j)
    {                                {
       i = i - 10;                      System.out.println(i);
       System.out.println(i);           i = i - 10;
    }                                }


5.  i = 30;                      6.  i = 10;
    j = 10;                          j = 10;
    if (i > 10 + j)                  if (i > 10 + j)
       while (i > j)                    while (i > j)
       {                                {
          i = i - 10;                      i = i - 10;
          System.out.println(i);          System.out.println(i);
       }                                }
    else                             else
       while (j >= i)                   while (j >= i)
       {                                {
          j = j - 10;                      j = j - 10;
          System.out.println(j);           System.out.println(j);
       }                                }


7.  i = 30;                      8.  for (i = 1 ; i <= 10 ; i++)
    j = 10;                          {
    while (i >= j)                      if (i == 2)
    {                                      System.out.println("hello");
       if (i > j + 10)                  else if (i == 3)
          System.out.println("yes");       System.out.println("goodbye");
       else                             else if (i == 4)
          System.out.println("no");         System.out.println("why");
       i = i - 10;                      if (i < 5)
    }                                      System.out.println("help");
                                        if (i > 6)
                                           System.out.println("blue");
                                     }



9.  w = 0;                           10.   w = 0;
    for (h = -2; h <= 5; ++h)              for (h = 10; h > 0; --h)
       w = w + h;                              System.out.print(w);
       System.out.println(w);

11. n = 1;                           12.   for (x = 1; x <= 5; x++)
    for (k = 2; k <= 5; k++)                   System.out.println(x);
    {                                      System.out.println(x);
       n = k - 2 * 3;
       System.out.println(k + "  " + n);
    }

13.  Given the following program segment:

          sum = 0;
          finished = false;
          count = 0;
          while (count <= 8 && !finished)
          {
             number = getkeybd.nextInt();
             if (number > 0)
                sum += number;
             else if (number == 0)
                finished = true;
             count++;
          }
          System.out.println(sum + "  " + count);

     What would be the output given this data?
        9 -3 4 6 0 5 6 0 5

14.  What does the following program segment do?

     punctuation = 0;
     letters = 0;
     digits = 0;
     System.out.println("enter any character or '/' to quit:  ");
     tempstr = getkeybd.next();
     character = tempstr.charAt(0);
     while (character != '/')
     {
         if (character == ',' || character == '.')
            punctuation++;
         else if (character >= 'a' && character <= 'z' ||
                  character >= 'A' && character <= 'Z')
            letters++;
         else if (character >= '0' && character <= '9')
            digits++;
         System.out.println("enter any character or '/' to quit:  ");
         tempstr = getkeybd.next();
         character = tempstr.charAt(0);
     }
     System.out.println(punctuation + "  " + letters + "  " + digits);

15.  Input a character and a number from the user.  Print "number" number of
     lines of output with the character printed once on each line.



16. Given the following code, change the loop to an event controlled
loop that will exit when the user enters a negative number of hours
as the sentinel:

     System.out.println("Enter the number of employees: ");
     numEmployees = getkeybd.nextInt();
     totpay = 0;
     empCount = 0;
     while (empCount < numEmployees)
     {
        System.out.println("Hours: ");
        hours = getkeybd.nextInt();
        System.out.println("Rate: $");
        rate = getkeybd.nextDouble();
        pay = hours * rate;
        System.out.println("Employee pay is : $ " + pay);
        totpay += pay;
        empCount++;
     }
     System.out.println("Total payroll is $ " + totpay);


17. Write the statements to read in a group of exam scores ranging in
value from 0 to 100. Your program should count and print the number
of outstanding scores (90 to 100), satisfactory scores (70 to 89), and
the number of unsatisfactory scores (0 to 69). Stop reading exam scores
when a negative value is entered.