JavaScript Control Structures

JavaScript Control Structures

by DeLaina Pruitt

Multiple Choice

What will the following program print when run?

for (var j = 0; j < 2; j++) {

for (var i = 6; i > 4; i--){

println (i);

• 4

  5

  4

  5

• 6

  5

  4

  6

  5

  4

• 6

  5

  6

  5

• 0

  2

  6

  4

Multiple Choice

The following code continually asks the user for a password until they guess the correct password, then ends. But there is one problem.

var SECRET_PASSWORD = "karel";

function start(){

while(true){

var password = readLine("Enter your password: ");

if(password == SECRET_PASSWORD){

println("You got it!");

}

println("Incorrect password, please try again.");

}

}

• Change the true in line 4 to be password != SECRET_PASSWORD so that the program doesn’t loop infinitely

• Change the true in line 4 to be password == SECRET_PASSWORD so that the program doesn’t loop infinitely

• Add a break; statement after line 7 so that the program doesn’t loop infinitely

• Put line 9 inside of an else statement

Multiple Choice

What is the value of the boolean variable canVote at the end of the program?

var age = 17;

var isCitizen = true;

var canVote = age >= 18 && isCitizen;

• True

• False

• Yes

• none, there is a syntax error in this code

Multiple Choice

What will be the output of this program?

var number = 5;

var greater_than_zero = number > 0;

if (greater_than_zero){

println(number);

}

• 0

• 5

• True

• Nothing with print

Multiple Choice

What will be the output of this program?

var number = 5;

var greater_than_zero = number > 0;

if (greater_than_zero){

if (number > 5){

println(number);

}

}

• 0

• 5

• True

• Nothing will print

Multiple Choice

What is printed by the following program?

var isRaining = false;

var isCloudy = false;

var isSunny = !isRaining && !isCloudy;

var isSummer = false;

var isWarm = isSunny || isSummer;

println("Is it warm: " + isWarm);

• Is it warm: true

• Is it warm: false

• Is it warm: yes

• Is it warm: no

Multiple Choice

What is printed by the following program?

var numApples = 10;

var numOranges = 5;

if(numApples < 20 || numOranges == numApples){ println("Hello, we are open!");

} else {

println("Sorry, we are closed!");

} println("Sincerely, the grocery store");

• Hello, we are open! Sincerely, the grocery store

• Sorry, we are closed!

  Sincerely, the grocery store

• Hello, we are open!

• Sorry, we are closed!

• Sincerely, the grocery store

Multiple Choice

What will the following program print when run?

var above16 = true;

var hasPermit = true;

var passedTest = false;

if (above16 && hasPermit && passedTest){

println("Issue Driver's License");

} else {

if (above16 || hasPermit || passedTest) {

println("Almost eligible for Driver's License");

} else {

println("No requirements met.");

}

}

• Issue Driver’s License

• Almost eligible for Driver’s License

• No requirements met.

• Nothing will print

Multiple Choice

We want to print the phrase “CodeHS is the best” exactly 25 times. What kind of control structure should we use?

• If statement

• While loop

• Break statement

• For loop

Multiple Choice

What is the output of the following program?

var result = 0;

var max = 5;

for(var i = 0; i < max; i++){

result += i;

}

println(result);

• 15

• 10

• 0

• 12345

Multiple Choice

What will the following program print when run?

var numberOne = 5;

var numberTwo = 10;

if (numberOne == 5) {

println(1);

}

if (numberOne > 5) {

println(2);

}

if (numberTwo < 5) {

println(3);

}

if (numberOne < numberTwo) {

println(4);

}

if (numberOne != numberTwo) {

println(5);

}

• 1

• 1

  3

  5

• 1

  4

• 1

  4

  5

Multiple Choice

What is the last thing printed by the following program?

var start = 30;

var stop = 10;

for(var i = start; i >= stop; i-=5){

if(i % 2 == 0){

println(i * 2);

} else {

println(i);

}

}

• 10

• 20

• 30

• 60

Multiple Choice

We want to simulate constantly flipping a coin until we get 3 heads in a row. What kind of loop should we use?

• While loop

• For loop

• Variable loop

• Infinite loop

Multiple Choice

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

var i = 0;

while(i < 10){

println("hello");

}

• 9

• 11

• This code will loop infinitely

• 10