1. Loops

2. Review Control Structure – making decisions if-statement Program Design Understand what you want to do Design your solution Write and test your code Consider alternatives

3. Overview Loops Array basics

4. Loops A loop enables you to repeat a series of commands in your program. There are a few different types of loop structures, but will focus on the while loop today. A loop must have the following three components: A sentry or guard that will stop the program from repeating. This is called a condition. A block of code to repeat. A way to make the condition false.

5. While loop format int i = 0; while ( i<10 ) { System.out.println(i); i=i+1; } System.out.println(“Done!”); Condition – like an if-statement. Some type of true/false question Curly braces – form a box that has the lines of code you want to repeat. Increment/decrement – will increase/decrease the value of i so that the condition will become false To Do: copy this code into your TestMe class. Compile & execute. What happens?

6. Exercise Modify the code you just wrote so that the loop will count backwards.

7. Array Basics Variables hold single values An array can hold multiple values of the same type. It is like a list. For example, a list of grades or characters in a word. Each line in the array is called an ‘element’ double gradeschar charactersInWord 99.0 85.6 68.1 79.6 ‘p’ ‘e’ ‘a’ ‘c’ ‘e’

8. Array Basics How do you assign or retrieve values? Every element is identified by a unique number called an index. The index always starts with 0 and increases by 1 until the end of the list. The array has a length with represent how many elements it contains double gradeschar charactersInWord 099.0 185.6 268.1 379.6 0‘p’ 1‘e’ 2‘a’ 3‘c’ 4‘e’ Length = 4 Length = 5

9. Hangman Game A game that Reads a user’s guess Checks to see if the guess is a character in the hidden word If it is then the character replaces each mask character in position. If the player guesses a wrong character then the hangman is advanced one body part at a time. If the player misses 6 guesses they lose. If the player guesses the word within 6 wrong guesses, then they win.