Objectives

Objectives
Describe and use boolean logic
Trace the flow of a program based on its code
Predict the output from if/else and switch statements
Explain the differences between for loops and while loops, and when to use each
Implement if/else logic, for and while loops, and combinations

Motivation (Why?)

Conditionals and loops are fundamental to all programming in every language and paradigm.

Analogy (What?)

Condtionals are like a choose your own adventure book.

Loops are like a room of people introducing themselves.

Examples (How?)

Basic Boolean Operators

English "and" "or" "not" or "bang" "double bang"
Javascript && || ! !!
e.g. a && b a || b !b !!b
English A and B A or B not B not NOT B

Boolean Comparison Operators

strict equality loose equality not strictly equal not loosely equal greater than less than greater than or equal to less than or equal to
=== == !== != > < >= <=

if/else

if (badWeather) {
  takeTheBus();
}

if (!badWeather) {
  walkToWork();
}

if (badWeather) {
  takeTheBus();
} else {
  walkToWork();
}

else if

if ( hasCar ) {
    // drive it!
} else if ( hasBike ) {
    // ride it!
} else if ( hasTransitPass ) {
    // take the bus!
} else {
    // better start walking!
}

switch

switch (row){
    case 1:
        price = 0.25;
    case 2:
        price = 0.50;
    case 3:
        price = 0.75;
    case 4:
        price = 1.00;
    default:  // the rest of the products (rows 5-7)
        price = 1.25
}
// ^ vending machine with prices organized by row!

while/for loops

var m = ["Bill", "Nicki", "Kelly"]
for (i = 0; i < m.length; i++) {
  console.log(m[i] + " is a nice person")
}

var movieData = {director: "Burton", year: 1993, title: "The Nightmare Before Christmas", price: 4.55}
for (key in movieData){
    if (movieData.hasOwnProperty(key)){
        console.log(key + ": ", movieData[key]);
    }
}

while (timeBeforeWork > 180000) { // Remember JS counts time in milliseconds
  hitSnooze()
}

Challenges

Docs & Resources

Loops - JSforcats </br> Conditionals - Codeacademy </br> Loops - CodeAcademy </br>

External Reading and Tutorials

Javascripting </br>