Question

You need to write a program that has karol take all the tennis balls where karel is standing. If there is any, karel should end up with no tennis balls on that spot. Which control structure do you need to use?

1) if statement
2) for loop
3) while loop
4) switch statement

Answer 1

To program Karel to remove all tennis balls from its current spot, a while loop is the most appropriate control structure to use. It allows Karel to keep picking up balls until there are none left, ensuring the spot ends up empty.

Step-by-step explanation:

If you're looking to write a program where Karel the robot takes all the tennis balls from where it's standing, you should use a while loop. A while loop will continue to execute as long as the condition within it remains true. In the case of Karel, the condition would be whether or not there is a tennis ball on the current spot.

The structure of the while loop will look something like this:

while (tennisBallsPresent()) {
pickTennisBall();
}

This loop will repeatedly tell Karel to pick up a tennis ball if there is one present. As soon as there are no more tennis balls, the condition will become false, and Karel will stop picking tennis balls, leading to an empty spot.

The if statement, for loop, and switch statement are not suitable for this situation. An if statement only executes once, a for loop requires knowledge of how many iterations to run for in advance, and a switch statement is used for making a decision based on different cases.