Build a Quiz Challenge, Part 1 Solution

Welcome back. 0:00 How did you do on the challenge? 0:01 If you got the quiz working, good for you. 0:03 If you didn't, that's okay. 0:05 My programming challenges are becoming more difficult as I 0:06 teach you more JavaScript. 0:09 Let me show you how I programmed the quiz. 0:11 The first step is to create an array of questions. 0:14 Because I want to include a question and 0:18 an answer, I'll use a two dimensional array. 0:20 So each array inside the question array will contain two elements, a question and 0:23 its answer. 0:28 [BLANK_AUDIO] 0:28 I'll add a couple more questions. 0:34 [BLANK_AUDIO] 0:35 To keep the quiz simpler, 0:47 I'm just going to ask questions that have numbers for answers. 0:48 Because I want to keep track of how many questions the player answers correctly, 0:52 I'll need a variable to track correct answers. 0:56 [BLANK_AUDIO] 0:59 In addition, I'll define a few more variables. 1:02 [BLANK_AUDIO] 1:04 These variables don't have anything in them yet, 1:10 I'll fill them with values later. 1:12 But it's good programming practice to include variables at the top of 1:14 a script or for variables you use in a function at the beginning of the function. 1:17 That way, you or anyone else looking at your code can see in 1:22 a single place all the variables that are used in the script. 1:25 Now that we have an array of questions, it's time to ask them. 1:30 To do that, we should loop through the array, ask a question and 1:34 see if the player answers correctly. 1:38 I'll use a for loop for this. 1:40 [BLANK_AUDIO] 1:41 This should look pretty familiar to you by now, 1:45 it just creates a loop that runs as many times as there are items in the array. 1:48 I'm gonna pull some information out of each array item and 1:53 store it in a variable. 1:56 First, I wanna capture the question. 1:58 [BLANK_AUDIO] 1:59 Because this is a two dimensional array, 2:03 we first have to access an element from the outer array. 2:06 Then to access the question, 2:10 we have to get to the item at the first position, which is at the zero index. 2:12 The answer is at index one. 2:17 [BLANK_AUDIO] 2:19 Now we can ask the question and get a response. 2:25 [BLANK_AUDIO] 2:28 I didn't have to create this question variable, 2:31 I could've just added the array notation here like this. 2:34 However, I find it easier to read and understand my program if I used well-named 2:39 variables like question and answer and store the proper information in them. 2:44 Because the return value of the prompt dialog is always a string, 2:50 I need to convert it to a number. 2:53 This takes the value inside the response variable, converts it to a number, 2:56 then stores that number back into the response variable. 3:00 Here's a place I could shorten my code. 3:03 I could just wrap the parseInt method around the prompt method. 3:06 [BLANK_AUDIO] 3:09 With programming, you work your way out from the innermost set of parentheses. 3:13 For example, first we pass a string, the question, to the prompt method. 3:18 It returns a string value, which is then passed to the parseInt method. 3:23 I'll actually keep my code like this, I think it's simpler, and 3:28 easier to read, and I'll delete this line. 3:31 Our program isn't done yet. 3:34 But there's enough code here, that we can at least test to make sure that 3:36 the questions are being asked correctly. 3:39 I'll save the file and preview the workspace. 3:42 [BLANK_AUDIO] 3:44 So far, so good. 3:49 Now let's see if the response matches the answer. 3:51 We do this using a conditional statement. 3:54 [BLANK_AUDIO] 3:56 If the response does match the answer, 4:01 then we can increase the number in the correct answers variable by one. 4:03 Let's create a message and print it to the screen. 4:08 [BLANK_AUDIO] 4:10 All right, let's see how this works. 4:25 I'll save the file and preview the workspace. 4:26 [BLANK_AUDIO] 4:28 Awesome. 4:32 The quiz asks questions and keeps track of correct answers. 4:33 In the next video, 4:37 I'll present you with another challenge that will improve on this quiz. 4:38