14. JavaScript Functions.md

JavaScript Functions

Function Example 1

function greet() {
    console.log("Hello there");
}
greet();

Output

Hello there

---

Function Example 2

function greet() {
    console.log("Hello there");
}
greet();
console.log("After function call.");

Output

Hello there
After function call

---

Function Example 3

function greet() {
    console.log("Hello there");
}
greet();
greet();
greet();

Output

Hello there
Hello there
Hello there

---

Function arguments

Function Arguments Example 1

function greet(name) {
    console.log("Hello " + name);
}

greet();

Output

Hello undefined

---

Function Arguments Example 2

function greet(name) {
    console.log("Hello " + name);
}

greet("Jude");

Output

Hello Jude

---

Function Arguments Example 3

function greet(name) {
    console.log("Hello " + name);
}

greet("Jude");
greet("Jack");

Output

Hello Jude
Hello Jack

---

Passing Multiple Arguments

function addNumbers(n1, n2) {
    let result = n1 + n2;
    console.log("The sum is " + result);
}

let number1 = 6.6;
let number2 = 2.5;
addNumbers(number1, number2);

Output

The sum is 9.1

---

Return Value from a Function

function addNumbers(n1, n2) {
    let result = n1 + n2;
    return result;
}

let sum = addNumbers(6.6, 2.5);
console.log("The sum is " + sum);

Output

The sum is 9.1

JavaScript Built-in Functions

const num = 9;
const squareRoot = Math.sqrt(num);
console.log(`The square root of ${num} is ${squareRoot}`);

Output

The square root of 9 is 3

---

Programming Task

Can you create a program that can tell us if someone is eligible to vote? For this, Create a function canVote that accepts the age of the person. If the age is above 18, then return true else false Call the function for ages 17, 20 and 65 to verify if it is working correctly or not.

Solution:

function canVote(age) {
    if (age > 18) {
        return true;
    } else {
        return false;
    }
}

const result1 = canVote(17);
console.log(result1);
const result2 = canVote(20);
console.log(result2);
const result3 = canVote(65);
console.log(result3);

Output

false
true
true

---

Programiz Quiz

Q. What will be the output of the following code?

console.log(sqrt(9));

1. 3
2. 81
3. error
4. None of the above

Answer: 1