While Loops Review

While Loops Review#

These questions are to assess your understanding of the while loops.

Question 1

while loops are typically used as definite loops.

See Answer

False

We will typically use while loops for what we call indefinite loops, meaning that when we write a while loop, we will write it in such a way that it runs till a condition is false.

Question 2

Let’s write a while loop header! Say I’m writing a while loop that should loop until some variable x has value -1. Which test ensures my code will loop correctly?

while (x == -1)
while (x > -1)
while (x != -1)
while (x < -1)

See Answer

Option 4 is correct!

The loop when end when x == -1. Try going through the control flow of this for loop header for practice.

Question 3

What is the output of the following program:

int num = 1; // initialization
while (num <= 200) { // test
    System.out.print(num + " "); // body
    num = num * 2; // update
}

```
1 2 4 8 32 64 128
```
```
1
2
4
8
16
32
64
128
```
```
1 2 4 16 32 128 200
```
This will run forever and never stop

See Answer

Option 1 is correct!

We keep multiplying num by 2 until the number is bigger than 200