W4D3 Breakout Closures

closureExample.js

/*
 * Question: What is the difference between the two ways of declaring functions in JavaScript?
 */



//
// Declaring a function with var.
//

// console.log(sayHello); // Outputs undefined because var sayHello is hoisted up.
sayHello() // Doesn't work. because sayHello is undefined

var sayHello = function() {
  console.log("Hello");
}

sayHello() // Works
// Takeaway: You cannot call a function defined with var before it is defined



//
// Declaring a function with the function keyword.
//

sayHello() // Works
function sayHello() {
  console.log("Hello");
}
sayHello() // Works

functionDefinition.js

/*
 * Question: What is the difference between the two ways of declaring functions in JavaScript?
 */



//
// Declaring a function with var.
//

// console.log(sayHello); // Outputs undefined because var sayHello is hoisted up.
sayHello() // Doesn't work. because sayHello is undefined

var sayHello = function() {
  console.log("Hello");
}

sayHello() // Works
// Takeaway: You cannot call a function defined with var before it is defined



//
// Declaring a function with the function keyword.
//

sayHello() // Works
function sayHello() {
  console.log("Hello");
}
sayHello() // Works

guessingGame.js

var readline = require("readline");

var read = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

console.log("Welcome to the Math Game!");

// Sample Output
// ===================
// Welcome to the Math Game!
// Player 1: What is 88 + 123? 211
// You guessed correctly!
// Player 2: What is 12 + 19? 40
// You guessed wrong! 2 lives left.
// ... eventually
// Player 2: What is 100 + 1? 102
// YOU'RE DEAD. Player 1 for the win!

// Things our program will have to do
// generate two random numbers
// generate an answer
// accept input from the player
// keep track of the player's lives
// every time the user enters an answer and the answer is wrong, check if the game ended


function generateQnA() {
  // generate two random numbers
  var num1 = Math.floor(Math.random() * 100)
  var num2 = Math.floor(Math.random() * 100)
  var question = num1 + " + " + num2;
  var answer = num1 + num2;
  return {question: question, answer: answer};
}

function askQuestion() {
  // ask player1 a question
  var question = generateQnA();
  console.log("Player: What is " + question.question + "?");
  read.question("Answer: ", function(answer) {
    if(question.answer === parseInt(answer)) {
      console.log("CORRECT");
    } else {
      console.log("WRONG");
    }
    askQuestion();
  });
}

askQuestion();