chapter05.js

// ## Coding time!

// ### Improved hello

// Complete the following program so that it asks the user for his first and last names, then show the result of the `sayHello()` function.

// ```js
//Say hello to the user
function sayHello(firstName, lastName) {
 const message = `Hello, ${firstName} ${lastName}!`;
 return message;
}

// TODO: ask user for first and last name
// TODO: call sayHello() and show its result
// ```

const firstName = prompt('Enter your first name: ')
const lastName = prompt('Enter your last name: ')

sayHello(firstName, lastName);


// ### Number squaring

// Complete the following program so that the `square1()` and `square2()` functions work properly.

// ```js
// Square the given number x
function square1(x) {
   // TODO: complete the function code
   return Math.pow(x,2);
 }

// // Square the given number x
 const square2 = x => Math.pow(x,2);// TODO: complete the function code

console.log(square1(0)); // Must show 0
console.log(square1(2)); // Must show 4
console.log(square1(5)); // Must show 25

console.log(square2(0)); // Must show 0
console.log(square2(2)); // Must show 4
console.log(square2(5)); // Must show 25
// ```

// When it's done, update the program so that it shows the square of every number between 0 and 10.

for(i = 0; i <= 10; i++){
 console.log(square1(i));
}


// !!! info

//     Writing 10 dumb calls to `square()` is forbidden! You know how to repeat statements, don’t you? ;)

// ### Minimum of two numbers

// Let's pretend the JavaScript `Math.min()` function doesn’t exist. Complete the following program so that the `min()` function returns the minimum of its two received numbers.

// ```js
// // TODO: write the min() function

function min(n1,n2){
 if(n1 > n2){
  return n2
 } else {
  return n1
 }
}

 console.log(min(4.5, 5)); // Must show 4.5
 console.log(min(19, 9));  // Must show 9
 console.log(min(1, 1));   // Must show 1
// ```

// ### Calculator

// Complete the following program so that it offers the four basic arithmetical operations: addition, subtraction, multiplication and division. You can use either a function declaration or a function expression.

// ```js
// // TODO: complete program
function calculate(n1, operator, n2){
 switch(operator){
  case '+':
   return n1 + n2;
  case '-':
   return n1 - n2;
  case '*':
   return n1 * n2;
  case '/':
   return n1 / n2;
 }
}

 console.log(calculate(4, "+", 6));  // Must show 10
 console.log(calculate(4, "-", 6));  // Must show -2
 console.log(calculate(2, "*", 0));  // Must show 0
 console.log(calculate(12, "/", 0)); // Must show Infinity
// ```

// ### Circumference and area of a circle

// Write a program containing two functions to calculate the circumference and area of a circle defined by its radius. Test it using user input.



function calculateCircumference(radius) {
 return 2*Math.PI* radius;
}

function calcuclateAreaOfCircle(radius) {
 return Math.PI * Math.pow(radius,2);
}

const radius = parseFloat(prompt('Enter the radius of the circle: '));
calculateCircumference(radius)
calcuclateAreaOfCircle(radius)

// Here are some tips for solving this exercise:

// * Circumference and area calculation formulas should be part of your secondary school memories... Or a Google click away :)
// * The value of number π (Pi) is obtained with `Math.PI` in JavaScript.
// * You might want to use the [exponentiation operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators) `**` to perform computations.

// ```js
// console.log(2 ** 3); // 8: 2 * 2 * 2
// console.log(3 ** 2); // 9: 3 * 3
// ```