Learn

There are a few keywords we can use to add further control flow to our loops. Typically, they work with a series of nested loops, where one loop is written entirely within the body of another loop. These keywords are often used to limit while loops and prevent them from creating infinite loops.

BREAK

At any point within a loop block, you can end it by using the break keyword.

while (playerIsAlive) { // this code will keep running if (playerIsAlive == false) { // eventually if this stopping condition is true, // it will break out of the while loop break; } } // rest of the program will continue

You’ve already seen the break keyword— it’s the same keyword that is used in switch statements.

CONTINUE

The continue keyword is used to bypass portions of code. It will ignore whatever comes after it in the loop and then will go back to the top and start the loop again.

int bats = 10; for (int i = 0; i <= 10; i++) { if (i < 9) { continue; } // this will be skipped until i is no longer less than 9 Console.WriteLine(i); }

Here, the program starts in the for loop, then hits the if statement. Since there is a continue in the if statement, it will bypass the Console.WriteLine() statement until the condition in the if statement is no longer true. So while the loop starts at 0, nothing will print to the console until i is equal to 9.

RETURN

The return keyword is another way to exit a loop, specifically loops that are used within a method. When a return is used within such a loop, it breaks out of the loop and returns control to the point in the program where the method was called.

class MainClass { public static void Main (string[] args) { UnlockDoor(); // after it hits the return statement, it will move on to this method PickUpSword(); } static bool UnlockDoor() { bool doorIsLocked = true; // this code will keep running while (doorIsLocked) { bool keyFound = TryKey(); // eventually if this stopping condition is true, // it will break out of the while loop if (keyFound) { // this return statement will break out of the entire method return true; } } return false; } }

You should only use return if you need to exit a method because it will break out of all loops. If you only want to break out of one loop and not exit a method, use break.

Instructions

1.

You’ve decided to go back to the pomodoro application. This time, you don’t want the alarm to ring endlessly. Once it rings 3 times, it should shut off even if the button has not been clicked.

Create a variable that will keep track of how many times the alarm has gone off.

Note that we have temporarily set the initial value of buttonClick to true. Otherwise, running the code as is would result in an infinite loop! You will update the starting value of buttonClick in a later step.

2.

Inside the do...while loop, increase the count every time the alarm goes off.

3.

The program should break out of the loop if the count variable reaches three.

Write a statement that checks if the count variable has reached three, and when it does, have it break out of the do...while loop.

Now, you can update the starting value of buttonClick to false to see the alarm ring three times.

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