Java while loops

Input the number of cousins which an unknown quantity of people have, stopping when a negative number is input. Work out the average and the maximum number of cousins. The rest of this quiz will analyse and produce a solution to this problem.

Should you use a while loop or a for loop?

• while loop

• for loop

Answer explanation

It's for an unknown number of people so that's the right answer!

Doing a SITC analysis, what should you SELECT as the variable for the while loop?

(Problem again:  

Input the number of cousins which an unknown quantity of people have, stopping when a negative number is input. Work out the average and the maximum number of cousins.)

• number of cousins

• maximum number of cousins

• average number of cousins

• height of the cousins

Answer explanation

We are inputting the number of cousins for many people so that is the right answer.

How will you initialise the number of cousins?

• numCousins = 0

• Input numCousins

• Output numCousins

• numCousins = 10

What will you test in your while loop?

• numCousins >= 0

• numCousins < 0

• numCousins == 0

To CHANGE the variable, we will (a)   numCousins again

Is this code correct?

int numCousins;

numCousins = Double.parseDouble(JOptionPane.showInputDialog("Input number of cousins (-ve to stop)"));

• Yes

  All good to declare and input an int.

• No

  It should be Integer.parseInt

• No

  It should be Int.parseInt

• No

  It should say:

  integer numCousins;

To find the maximum, you need to add this code:

• int max;

• max = 0;

• if (numCousins > max)

  {

  max = numCousins;

  }

• max = -10;

To find the average number of cousins, you'll need the following:

• int total;

• double average;

• int count;

• int average;

Every time a new numCousins is inputted in the while loop, we need to say:

• count++;

• count--;

• average = total / count;

• total = 0;

Every time a new numCousins is inputted, we also need to add this is the while loop:

• total = total + numCousins;

• total = total - numCousins;

• total = numCousins;

• total = 0;