# Day 1 - Introduction

## [< Home >](../README.md) | [Day 2 >>](./02_day_datatype.md)

### [Exercise Level 1](#exercise-level-1)

### Exercise Level 1

1. Write a single line comment which says, _comments can make code readable_
2. Write another single comment which says, _Welcome to 30DaysOfJavaScript_
3. Write a multiline comment which says, _comments can make code readable, easy to reuse_
   _and informative_

4. Create a variable.js file and declare variables and assign string, boolean, undefined and null data types
5. Create datatypes.js file and use the JavaScript **_typeof_** operator to check different data types. Check the data type of each variable
6. Declare four variables without assigning values
7. Declare four variables with assigned values
8. Declare variables to store your first name, last name, marital status, country and age in multiple lines
9. Declare variables to store your first name, last name, marital status, country and age in a single line
10. Declare two variables _myAge_ and _yourAge_ and assign them initial values and log to the browser console.

```sh
I am 25 years old.
You are 30 years old.
```

### Exercise Level 1


1. Write a single line comment which says, comments can make code readable

```js
// comments can make code readable
```

2. Write another single comment which says, Welcome to 30DaysOfJavaScript

```js
//Welcome to 30DaysOfJavaScript
```

3. Write a multiline comment which says, comments can make code readable, easy to reuse and informative

```js
/*        comments can make code readable,
           easy to reuse and informative  */
```

4. Create a variable.js file and declare variables and assign string, boolean, undefined and null data types

```js
//variable.js
let string = 'nevzat'
let number = 25
let boolean = true
let nulll = null
let any;     //undefined
```

5.Create datatypes.js file and use the JavaScript typeof operator to check different data types. Check the data type of each variable

```js
//variable.js

let string = 'nevzat'
let number = 25
let boolean = true
let nulll = null
let any; 

console.log(typeof (string) )  //String
console.log(typeof (number))   //Number
console.log(typeof (boolean))  //Boolean
console.log(typeof (nulll))    //Object
console.log(typeof (any))      //Undefined
```

6. Declare four variables without assigning values

```js
    let variable1;
    let variable2;
    var variable3;
    let variable4;
```

7. Declare four variables with assigned values

```js
variable1 = "nevzat"
variable2 = "ATALAY"
variable3 =  true;
variable4 = 25;
```

8. Declare variables to store your first name, last name, marital status, country and age in multiple lines

```js
let firstName = "nevzat"
let lastName = "atalay"
let old = 25
let isMarried = true
```

9. Declare variables to store your first name, last name, marital status, country and age in a single line

```js
let name = "nevzat",surName="atalay",age = 25, married = true
```

10. Declare two variables myAge and yourAge and assign them initial values and log to the browser console.

```js
let myAge= 25
let yourAge = 22

console.log("I am " + " " +  myAge + " " + "years old.") // I am 25 years old.
console.log("You are" + " " +  yourAge + " " +  "years old.") // You are 22 years old.
```

## [< Home >](../README.md) | [Day 2 >>](./02_day_datatype.md)