example code

Question 1

switching between asynchronous tasks

Answer 1

import asyncio

async def my.task(n):
> print(f”my.task: starting{n}”)
> await asyncio.sleep(n) # non-blocking delay

sync def sequential_main( ) :
> await my task ( 3 )
> await my task ( 1 )

async def gather_main( ) :
> await asyncio.gather( my_task ( 3 ) , my_task ( 1 ) )

–

• import asyncio
• async is a keyword for this function telling it to wait for other tasks to run for n seconds
• “await” to run both tasks in order, wait for each to finish before moving on
• call several tasks at once, not synchronous

Question 2

await asyncio.sleep(n)
is what?

Answer 2

non-blocking delay; run something else, then check if this finished execution

Question 3

declarative react example: return JSX display

Answer 3

import { useState } from “react”;

export default function App() {
const [count, setCount] = useState(0);

return (
> <div>

<div>
> <span>Count: {count}</span>
> {count > 5 ? <b> Yeah!</b> : <i> Click away...</i>}
</div>

> <button onClick={() => setCount(c => c + 1)}>Increment</button> </div>
);
}

–

• import useState hook
• define App, which can be exported from the file to move elsewhere
• const [count, setCount] = useState(0);
• return JSX display

Question 4

ES6 class, model of car

Answer 4

class Model extends Car {
constructor(name, mod) {
super(name);
this.model = mod;
}
show() {
return this.present() + ‘, it is a ‘ + this.model
}
}
const mycar = new Model(“Ford”, “Model T”);
mycar.show();

–

• class Model extends Car
• constructor with all args needed
• super; get name from extending Car class
• this.model for instance of class Model
• define and call show()

Question 5

find element with the id root, store in the variable “container”

Answer 5

const container = document.getElementById(‘root’);

Question 6

implement runnable

Answer 6

public class MyRunnable implements Runnable {

@Override
public void run() {
    System.out.println("Thread is running...");
}

public static void main(String[] args) {
    Thread thread = new Thread(new MyRunnable());
    thread.start();  // starts the new thread
} }

–

• public class myrunnable implements the built-in interface runnable
• override run method, output message
• public static void main(String[] args)
• Thread thread to instantiate new thread
• thread.start to begin executing a new thread

Question 7

extend thread

Answer 7

class MyThread extends Thread{

@Override
public void run(){
    
    System.out.println("Thread is running");
} }

public class Main {

public static void main(String[] args){
    
    MyThread t1 = new MyThread();
    MyThread t2 = new MyThread();
    
    t1.start();  
    t2.start();  
} }

–

• MyThread extends the class Thread
• extend (public void) run() to execute a message when it runs
• create thread objects in Main class main(String[] args)
• run() or t.start();

Question 8

value of container (root) becomes React object in DOM

Answer 8

const root = ReactDOM.createRoot(container);

Question 9

render the root React object

Answer 9

root.render(<p>Hello</p>);

Question 10

imperative javascript

Answer 10

for (let i = 0; i < numbers.length; i++) {
if (numbers[i] > 10) {
result.push(numbers[i]);
}
}
–
tells the system how to do something step by step

Question 11

functional test

Answer 11

class LoginFunctionalTest {

private WebDriver driver;

@BeforeEach
void setUp() {
    driver = new ChromeDriver();
    driver.get("https://example.com/login");
}

@Test
void testLoginSuccess() {
    WebElement usernameField = driver.findElement(By.id("username"));
    WebElement passwordField = driver.findElement(By.id("password"));
    WebElement loginButton   = driver.findElement(By.id("login-btn"));

    usernameField.sendKeys("user1");
    passwordField.sendKeys("secret123");
    loginButton.click();

    WebElement welcomeMessage = driver.findElement(By.id("welcome"));
    Assertions.assertTrue(welcomeMessage.isDisplayed());
}

Question 12

unit test

Answer 12

class CalculatorTest {

@Test
void testAdd() {
    Calculator calc = new Calculator();
    int result = calc.add(2, 3);
    assertEquals(expectedresult, result);
} }