Keywords
- Basic Data Types
- Conditionals
- Loops
- Arrays
- Objects
- Chrome
debuggerkeyword - VS Code
- Terminal
- Files / Folder Navigation
- Git & Github
Note: The information provided here is for your convenience. Please follow a long in class and refer to the in-class discussion for what you should be doing.
Getting started:
Included in this repo are the following files:
app.js- This is where you will write all of your codeindex.html- You will run this HTML file in your browser to run your codestyle.css- Ignore for this project. This is to style the page, but your app will not be interacting directly with the webpage.readme.md- That is what you are reading right now. The file is in markdown format (.md), it's straight forward way to organize text content that Github understands. You don't need to know much more than that about it right now.
Create a guessing game that allows users to guess a secret number. You will need to use the built in “prompt()” function to capture the user input when the program is running. Once you have the user’s input, you can compare it with your secret number and use the built in “alert()” function to send back the appropriate message.
The functions alert and prompt are built into the web browser. And since our javascript code runs in the web browser, we can use them.
Alert: https://developer.mozilla.org/en-US/docs/Web/API/Window/alert
Prompt: https://developer.mozilla.org/en-US/docs/Web/API/Window/prompt (Please read the documentation on prompt, make sure you understand what result is and the parameters)
_Hints on debugging: _ Firstly, you WILL have lots of bugs and errors in your code while you are building something. Everyone does, it’s normal and expected, it’s not just because you are new - but also a large part of writing code. The computer is picky, it needs things written a certain way, and it also has zero common sense. It does not know your intentions, only what exactly what you tell it to do. This means the problems in your code will likely fall in to either one of two categories:
Syntax Error - You misspelled something or the code structure is incorrect, e.g.
Variable spelled wrong:
var student = “Alice”; console.log(studnt); // Uncaught ReferenceError: stdnt is not defined
Missing closing parenthesis:
alert(“hello” / /Uncaught SyntaxError: Invalid or unexpected token
Logic Error - The code might run but it doesn’t do what you expect. OR the code doesn’t run, and something like a variable is in a format that is not what the computer expected. E.g.
Subtracting the number 10 from “Bob”, this returns Not a Number (NaN):
var name = “Bob”; console.log(name - 10); // NaN
Get used to reading and understanding error messages, it is a skill! First read the error message. Next, almost all errors you encounter will have a line number from where the error originated. That is the best place to start when you are trying to fix your code, find the line number and remember what the error message said.
Secondly, you should open Chrome’s console when you are running your program so you can read any error messages. Because we are using Chrome to run our program, we can use a special keyword called ‘debugger’ to pause our code while it is running and see what all of our variables look like. Just create a new line in your code where you want it to pause and type in “debugger”.
Using alert and prompt, write a program that asks the user to guess a number and then tells them if they were correct, or if they should have guessed higher or lower.
Main Function
Inputs:
(Number) Guess
Example Output:
(String) “Higher”, if Guess is lower than the secret number
Or
(String) “Lower”, if Guess is higher than the secret number
Or
(String) “Correct!” , if Guess is equal to the secret number
If the guess is higher or lower, ask the user to guess again. Your program should keep doing this until the guess is the same as the secret number. Check Your Work! Test out your code, make sure everything is working correctly. Also make sure you don’t see any errors in console.
Stuck? Try these exercises to get your brain going:
Before trying to solve a problem, do you understand what the problem is?
Write out what you are trying to accomplish in your own words
- Now break it down into smaller steps.
- E.g. What would half done look like?
List out what things MIGHT work
Is this problem different from anything you’ve seen before?
- What makes it so different?
- What does that mean you need to research / google?
Is there anything familiar in the problem?
Super Stuck? If you are still stuck on how to do this, share what you have done above and you can ask for a hint, or hang on for the class solution.
Done early? Look for opportunities to refactor (we will cover refactoring later). By far the most important skill to start working on right now: If someone were to read your code, would it be easy for them to read and understand without having you explain it?
Other things you can do:
Does your code seem repetitive? Use more functions
Name those functions appropriately.
If your functions are more than 5 lines or so, split it into smaller functions.
Once the user guesses the correct answer, let’s add a feature that tells them how many guesses it took them until they made the correct guess.
Main Function
Inputs:
(Number) Guess
Example Output:
“
“
(String) “Correct! It only took you 5 guesses!” , if Guess is equal to the secret number
Let’s update the last feature so that instead of just the number of guesses, we let the user know all of their previous guesses before they got the right answer.
Main Function
Inputs:
(Number) Guess
Example Output:
“
“
(String) “Correct! Your previous guesses were 100, 30, 50, 55!” , if Guess is equal to the secret number
Let’s add a feature that takes in the user’s name at the start of the game so we can make the messages more personalized.
Main Function
Inputs:
(String) Name
(Number) Guess
Example Output:
(String) “Sorry Alice, Guess Higher”, if Guess is lower than the secret number
Or
(String) “Sorry Alice, Guess Lower”, if Guess is higher than the secret number
Or
(String) “That’s Correct Alice! Your previous guesses were 100, 30, 50, 55!” , if Guess is equal to the secret number
Let’s add a feature that asks the user if they want to play again once they’ve made a correct guess.
Play Again Function
Inputs:
(String) “Yes”, Run main game function
(String) “No”, do nothing
Let’s add a feature that records the number of guesses for each unique name that is entered when the game is started. If someone with the same name played before, then when they get a correct answer, it tells them if they beat their previous attempt (less guesses is better).
Main Function
Inputs:
(String) Name
(Number) Guess
Example Output:
(String) “That’s Correct Bob! And you beat your previous attempt by 3 fewer guesses!” , if Guess is equal to the secret number and “Bob” played before with more guesses.
(String) “That’s Correct Alice! You did better in your last game by 3 fewer guesses.” , if Guess is equal to the secret number and Alice played before with less guesses.