Objectives

Expressions and Intro to Functions

• Given a working REPL interface, write and execute a statement that will print “hello world” using console.log
  • console.log("hello world!");

• Identify that strings are a list of characters defined by using double or single quotes**

• The string data type is a primitive data type that used to represent textual data.

• can be wrapped by either single or double quotation marks, best to choose one and stick with it for consistency.

• Given an arithmetic expression using +, -, *, /, %, compute its value

  console.log(25 % 7); // 4
  console.log(9 + 4); // 13
  console.log(2 + 4 * 5); // 22
  console.log(9 / 2); // 4.5
  console.log(10 - 3); // 7

• Given an expression, predict if its value is NaN
  • In general, any nonsensical arithmetic will result in NaN ; usually operations that include undefined.

• Construct the truth tables for &&, ||, !

  • Not Truth Table

    Input	Ouput
    !true	false
    !false	true

  • Or Truth Table | Input | Input | Output | | —– | —– | —— | | T | T | T | | T | F | T | | F | T | T | | F | F | F |

  • Not Truth Table | Input | Input | Output | | —– | —– | —— | | T | T | T | | T | F | F | | F | T | F | | F | F | F |

• Given an expression consisting of >, >=, ===, <, <=, compute it’s value

  console.log(24 > 3 && false); // false

• Apply De Morgan’s law to a boolean expression

  !(A || B) === !A && !B;
  !(A && B) === !A || !B;

• Given an expression that utilizes operator precedence, compute its value

  console.log((2 + 4) * 5); // 30

• Given an expression, use the grouping operator to change it’s evaluation

  console.log(2 + 3 * 4); // => 14
  console.log((2 + 3) * 4); // => 20

• Given expressions using == and ===, compute their values

  console.log(43 === "43"); // => false
  console.log(43 === "43"); // => true

• Given a code snippet using postfix ++, postfix –, +=, -=, /=, *=, predict the value of labeled lines

  let x = 7;
  x++;
  x - 2;
  x *= 3;
  console.log(x); // 24
  
  let i = 4;
  i + 3;
  console.log(i); // 4
  
  let i = 4;
  i += 3;
  console.log(i); // 7

• Create and assign a variable using let to a string, integer, and a boolean. Read its value and print to the console.

  let sent = "Hello I am a string.";
  let int = 2901;
  let bool = !true;

• Define a function using function declaration

  function cat(name) {
    if (name === "Berber") {
      return "He's the best boy in the whole world!";
    } else {
      return "Where is Berber?";
    }
  }

• Define a function that calculates the average of two numbers, call it, pass in arguments, and print it’s return value

  function avgOfTwo(num1, num2) {
    return (num1 + num2) / 2;
  }
  
  console.log(avgOfTwo(5, 11)); // => 8

• Identify the difference between parameters vs arguments
  • Parameters : Comma seperated variables specified as part of a function’s declaration.

  • Arguments : Values passed to the function when it is invoked.