Max iteration: Min iteration: Max iteration: Min iteration: Max iteration: Min iteration:

Transcription

1 Midterm Review Optional Worksheet 1. T/F 1. Numbers, booleans, and arrays are value types. 2. Value types have fields. 3. A constructor has no return type. 4. Classes define all properties and functions of an object. 5. The mod operator shows the remainder when two numbers are divided. 2. Given the following loops, what are the maximum and minimum numbers of iterations that each loop performs? function loop1(num: number): boolean { // assume num is a whole number < 3 for (let i: number = num; i < 10; i++) { if (i % 2 === 0) { return true; return false; function loop2(input: number): number { for (let i: number = 10; i >= 0; i--) { if (input < 0) { return input + 1; return input; Max iteration: Min iteration: function loop3(input: number): number { for (let i: number = 1; i < 10; i = i * 2) { if (input < 0) { input++; return input; Max iteration: Min iteration: Max iteration: Min iteration: 3. Given the following class, which constructions of a Rectangle object are valid? For those that are invalid, explain why. class Rectangle { length: number; width: number; color: string; name: string undefined; constructor(length: number, width: number, color: string, name?: string) { this.length = length; this.width = width; this.color = color; this.name = name;

2 (a). let a: Rectangle = new Rectangle(4, 2, green, myrectangle); (b). let b: Rectangle = new Rectangle(6, 3); (c). let c: Rectangle = new Rectangle(9, 4, orange, red ); (d). let d: Rectangle = new Rectangle(5, 2, blue, null); (e). let e: Rectangle = new Rectangle( green, 4, 5); (f). let f: Rectangle = new Rectangle(c.length, c.width, purple, f ); (g). Write your own construction of a Rectangle object below. 4. Consider the following code and answer the questions below. let hee: number = 4; let haw: number = hee; hee += 4; print("hee: " + hee); //a print("haw: " + haw); //b let haa: string[] = ["hello", "goodbye"]; let hoo: string[] = haa; haa[2] = "howdy"; hoo[1] = "hola"; print("hoo: " + hoo); //c print("haa: " + haa); //d a. What would be printed to the console at the line with the commented a? b. What would be printed to the console at the line with the commented b? c. What would be printed to the console at the line with the commented c? d. What would be printed to the console at the line with the commented d?

3 5. Draw the visualization depicted below. a. Draw a linked list of the following farm animals in the order they are given Rat Chicken Pig Cow Horse b. Redraw it after the following code runs. Assume head is the head Node variable of this linked list and we are given functions that we implemented in problem set 4. head.next = head.next.next; head = head.next; last(head).next = head; 6. Given the program below, answer the questions. class Person { constructor(name: string, age?: number) { this.name = name; if (age === undefined) { this.age = 0; else { this.age = age; age: number; name: string; celebratebirthday(who: Person): Person { return who.havebirthday(); havebirthday(): Person { this.age++; return this; function main() { let p1 = new Person( JC, 18); let p2 = new Person( Kit ); let name1: string = p1.havebirthday().name; let name2: string = p1.celebratebirthday(p2).havebirthday().name; let name3: string = p1.celebratebirthday(p2).celebratebirthday(p2).name; After the main function runs, write down the actual values stored in the following variables. name1 name2 name3 p1.age p2.age

4 7. class Node { data: string = ""; next: Node null = null; constructor(data: string) { this.data = data; tostring(): string { if (this.next === null) { return this.data + "-> null"; else { return this.data + "->" + this.next.tostring(); let first: Node = new Node("first"); let a: Node = new Node("a"); let b: Node = new Node("b"); let c: Node = new Node("c"); let d: Node = new Node("d"); let e: Node = new Node("e"); let f: Node = new Node("f"); Given the class to the left, fill in the boxes with the data of each Node, and then write out what will be printed on the bottom line. Node variable name a Output: b c d e f Node data a = b; a.next = c; c.data = f.data; c.next = f; d.next = b; e = d; e.data = a.data; first.next = e; b.next = c; c.next = f; print(first.tostring());

5 8. class Baz { arr: number[]; /* Implement part A here */ /* Implement part B here */ a. Create a constructor that takes in an array of numbers and assigns that array to the arr property (no initial value). b. Given the class to the left, implement a method named getsumodds that returns the sum of all the odd numbers in the arr property (Hint: use the modulo operator). c. Create a new object named foo of type Baz whose arr property is an array of the numbers 0 through 9. d. Print out the value returned by calling getsumodds on the foo object. /* Implement part C here */ /* Implement part D here */

6 Solution 1. FFTTT 2. 2,1; 11, 1; 4, 4; 3. invalid, invalid, valid, invalid, invalid, valid, ex: let g: Rectangle = new Rectangle(6, 3, black, g ); or: let g: Rectangle = new Rectangle(6, 3, black ); 4. 8; 4; hello,hola,howdy; hello,hola,howdy 5. (a) rat -> chicken -> pig -> cow -> horse -> null (b) pig -> cow -> horse -> (back to pig) 6. JC, Kit, Kit, 19, 4 7. b, b, f, b, b, f Output: first->b->b->f->f-> null 8. class Baz { arr: number[]; /* Implement part A here */ constructor(arr: number[]) { this.arr = arr; /* Implement part B here */ getsumodds(): number { let sum: number = 0; for (let i: number = 0; i < this.arr.length; i++) { if (this.arr[i] % 2 === 1) { sum += this.arr[i]; return sum; /* Implement part C here */ let foo: Baz = new Baz([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]); /* Implement part D here */ print(foo.getsumodds());