Unit 5 Review

Scope

100

What are the Local Variables and what are the Global Variables?

var y = 10

function double(x){
    var result = 2*x;
    return result;
}

var answer = double(y)

console.log(answer)

    •    Global variables: y, answer

    •    Local variables: x, result

200

Explain the difference between a local variable and a global variable

A local variable is defined within a function or block and is accessible only within that specific scope.

In contrast, a global variable is declared outside of any function or block, making it accessible throughout the entire program.

300

Which variables exist at point A? In other words, which variables are in scope at point A?

var x = 10;  

function doSomething(){  

    var y = 20;  

    // Point A  

}

function start() {

    var z = 30;  

    doSomething();

}

x and y

400

What will the following program print?

var num = 5;

function modifyNumber() {

    var num = 10;

    println(num);

}

modifyNumber();

println(num);

10

5

500

What is printed by the following program?

var name = "Global";

function showName() {

    var name = "Local";

    println(name);

}

println(name);

showName();

println(name);

Global

Local

Global

Arguments and Parameters

100

What are the parameters of the function?

function calculateArea(length, width) {  

    return length * width;  

}

length and width

200

True or false: Functions must have parameters.

False

300

How many parameters go into the function sum, and how many return values come out of the function sum?

function sum(first, second, third){
    var result = first + second + third;
    println(first);
    println(second);
    println(third);
    return result;
}

3 parameters go in, 1 return value comes out

400

What arguments are passed to the printNumbers method?

function start(){
    printNumbers(12, 17, 65);
}

function printNumbers(first, second, third){
    println(first);
    println(second);
    println(third);
}

12, 17, and 65

500

function printNumbers(x, y, z){
    println(y);
    println(z);
    println(x);
}

function start(){
    var zero = 1;
    var one = 2;
    var two = 0;
    printNumbers(zero, one, two);
}

2

0

1

Return Values

100

Which statement allows us to return values from functions?

return

200

True or False:

A return statement stops the execution of the function

True

300

What is returned and printed for the value of b?

function start(){
    var a = mystery(10, 14);
    var b = mystery(82, 28);

    println(a);
    println(b);
}

function mystery(x, y) {
    if (x < y){
        return x;
    }else{
        return y;
    }
}

28

400

What would the following print?

function mystery1(x){
   var result = x + 1;
   return result;
}

function mystery2(x, y){
   var result = x + y;
   return result;
}

function mystery3(x){
   x = mystery1(x);
   var result = x * x;
   return result;
}

function start() {

    var y = mystery2(15, 10);
    println(y);

}

25

500

What is the return value for this function?

function drawCircle(radius, color, x, y){
    var circle = new Circle(radius);
    circle.setColor(color);
    circle.setPosition(x, y);
    add(circle);
}

no return value

Other

100

Why do we write functions?

I. Make our code easier to understand by giving a readable name to a group of instructions
II. Avoid writing repeated code
III. Make our code reusable

200

What is the output of this code?

function calculateSum(num){  

    var total = 0;  

    for(var i = 1; i <= num; i++){  

        total += i;  

    }  

    println(total);  

}  

calculateSum(3); 

6

300

What does API stand for in computer science?

Application Programming Interface

400

Which of the following is true for an API?

I. Allows different devices to connect with each other
II. Allows for Interactivity between devices and software
III. Messenger program that takes requests and delivers the response back to the user
IV. Allows the creation of applications that access the features or data of an operating system, application, or other services
V. Specifies how software components should interact
VI. Used when programming graphical user interface (GUI) components

ALL

500

“It’s a bird! It’s a plane! No, it’s Superman!”
We want to write a function isSuperman that takes in two parameters isBird and isPlane and returns true if it is in fact Superman, and false otherwise.
If it’s not a bird and it’s not a plane, it must be Superman.

function isSuperman(isBird, isPlane){
    return !isBird && !isPlane;
}

QOTD

100

Do functions need to have return statements?

No, return statements are only needed if you need to pass back a value to the calling statement.

200

What is printed by the following program?

function main() {
    let a = 5;
    let b = 10;
    let c = 15;

    printValues(a, b, c);
}

function printValues(third, first, second) {
    console.log(first);
    console.log(second);
    console.log(third);
}

main();

10
15
5

300

The following function draws a rectangle on the canvas. What is the minimum number of arguments that must be used when calling the drawSquare() function?

function drawSquare(size, color) {
    let square = new Rectangle(size, size);
    square.setColor(color);
    square.setPosition(100, 100);
    add(square);
}

2

400

function subtract(x, y) {
    console.log(x + " minus " + y + " equals: " );
    let difference = x - y;

    return difference;
}

console.log(subtract(10, 5));

10 minus 5 equals:
5

500

function main() {
    let x = sumThree(1, 2, 3);
    console.log(x);
}

function sumThree(one, two, three) {
    let result = one + two + three;
    console.log(one);
    console.log(two);
    console.log(three);

    return result;
}

main();

1

2

3

6