JavaScript Control Structures

Which of the following is not a valid value for a boolean?

yes

What symbol represents the and operator in JavaScript?

&&

What symbol represents the or operator in JavaScript?

||

After the following code runs, what is the value of isWeekend?

var isSaturday = true;
var isSunday = false;
var isWeekend = isSaturday || isSunday;

true

What is the proper way to compare if two values are equal in a boolean expression in JavaScript?

==

What is the proper operator for "not equals" in JavaScript?

!=

How can we check if a variable num is even?

(num % 2 == 0) will be true

What kind of statement allows us to run a block code only if a certain condition is true?

if statement

What kind of statement allows us to run one block of code if one condition is true, and a separate block of code otherwise?

if/else statement

How many times will the following program print "hello"?

for (var i = 0; i < 5; i++) {
println("hello");
}

5

In the following code, what will be the last number to print to the screen before the program finishes?

for (var i = 0; i < 10; i++) {
if (i % 2 == 0) {
println(i);
} else {
println(2 * i);
}
}

18

How many times will the following code print "hello"?

for (var i = 3; i < 8; i++) {
println("hello");
}

5 **YES AGAIN

How many times will the following code print "hello"?

for (var i = 0; i < 8; i += 2) {
println("hello");
}

4

Why do we use constant variables?

All of the Above

Which of the following is a good example of a proper constant variable name?

var MAX_VALUE = 100;

What will be the value of sum after this code runs?

var START = 1;
var END = 4;

function start(){
var sum = 0;
for(var i = START; i <= END; i++){
sum += i;
}
}

10

Which of the following returns a random number between 1 and 10?

Randomizer.nextInt(1, 10)

How many possible values can Randomizer.nextBoolean() return?

2

How many times will this program print "hello"?

var i = 10;
while (i > 0) {
println("hello");
i--;
}

10

How many times will this program print "hello"?

var i = 50;
while (i < 100) {
println("hello");
}

This code will loop infinitely

What statement can we use inside of a loop to end it?

break

What is the term for the value that signals the end of user input?

sentinel

Which of the following is correct loop and a half structure?

while(true){
//code
if(condition){
break;
}
//code
}

4.10.5: Better Password Prompt

var SECRET = "abc123";

function start(){
while (true)
var password = ("What is the password? ");
if (password == "abc123") {
break;
}
}
}

Boolean

true or false value.

Logical Operator

Used to make logical associations between boolean values

OR Operator

Logical operator that ___ two boolean values. Written as ||. a || b will be true if a or b is true.

Not Operator

Logical operator that negates a single boolean value. Written as !. !a will be true if a is false, and false if a is true.

And Operator

Logical operator that ___ two boolean values. Written as &&. a && b will be true if both a and b are true.

Comparison Operator

Used to make comparisons between values.

If Statement

lets you ask a question to the program and only run code if the answer is true.

If-Else

Control structure that lets us run either one section of code or another depending on a test.

Event

an action (such as clicking the mouse or pressing a key on the keyboard) that a program detects and uses as input.

For Loop

lets us repeat code a fixed number of times.

Randomize

To generate or select a random object

Psuedorandom

Not actually random, but appears to be random

While Loop

Lets us repeat code as long as something is true

Infinite Loop

A loop that has no eay of stopping, and will keep looping forever

Sentinel

A constant that has the specific purpose of being the value that breaks out of a loop

Break Statement

Statement that breaks out of the current loop, without executing any more code in the loop

Loop-and-a-half

most often set with a while(true), that has a break statement in the loop body.