# All You Need For The First CLI App


> What is a CLI?

> CLI stands for **COMMAND LINE INTERFACE** . As the name suggests, it is used for interacting using some commands. Simply, it is a way of interaction with the user and browser without any graphics i.e majorly in plain text 


Anything you do consists of mainly three things : 
- Input
- Processing
- Output

The same you need to remember while building your FIRST CLI APP.


Before we jump to code, go check out the  [Basic Terminology](https://dailyblogs.hashnode.dev/basic-terms-before-starting-programming)  that would be used.

LET'S BEGIN , BY MAKING A DO YOU KNOW ME QUIZ !!!!

Let's make the app on the online IDE . I am using REPL.it .
Make your account and create a new REPL(language Node.js / javascript).

As we learned three things are a must , 
INPUT , PROCESSING AND OUTPUT .

For INPUT , we will be using [readline-sync](https://www.npmjs.com/package/readline-sync)  and for making our CLI app a little colorful we will be using [chalk](https://www.npmjs.com/package/chalk) .

In case , if you are not using REPL.IT or any other online IDE , begin with Step 1 . Rest can start with Step 2 as online IDE will automatically install the packages as you use them

**Step 1 :** To Install the packages :-         
-  npm install readline-sync
-  npm install chalk 

**Step 2 : ** To tell your app that we need the packages and we are going to use them .

```
const readLineSync = require('readline-sync');
const chalk = require('chalk');
``` 
**Step 3 :** Now we need to know the person's name who is playing the game , because w address people with their names.

```
const userName = readLineSync.question(
                                 chalk.cyanBright("What's your good name?")
                                 );
// chalk.cyanBright represents the color in which it will be visible.
``` 
**Step 4 :** We need an array to store all the questions and their correct answers. I am using one of the types in [readline-sync](https://www.npmjs.com/package/readline-sync) i.e the user can I/P answer only in a yes(y) or no(n). You can choose whatever you would like to , as per your choice from the docs.

Also initialise the score to 0;

```
var score = 0;
var questionListOne =[{
question:"She lives in Delhi.",
answer:false
},
{
question:"She has a younger brother.",
answer:true
},
{
question:"She has watched 'FRIENDS'.",
answer:false
},
{question:"She loves Pizza over Burger.",
answer:true},
{
question:"She does'nt know cooking,",
answer:true
}
]
``` 

**Step 5 : ** Now I need to map the questions , so I will be needing a for-loop. But in the loop I need to check whether the answer matches to what user has input , if it does , increase the score by 1 , and if it does'nt decrease the score by 1 or make no changes in the score.

```
function checkAns(ques,correctAns)
{
  var userAns = readLineSync.keyInYNStrict(chalk.bold.yellowBright(ques));
  if(userAns == correctAns)
  {
    console.log(chalk.greenBright(userName +" , Correct Answer"));
    score = score + 1;
     console.log(chalk.greenBright("Score = "+ score));
  }
  else
  {
    console.log(chalk.redBright(userName +" , Wrong Answer score remains same"));
  }
}
``` 

```
for(var i =0;i<questionListOne.length;i++)
{
  currQues =questionListOne[i]
  console.log(); // to give a empty line
  checkAns(currQues.question,currQues.answer)
}
```

**Step 6** :  Now comes the final step , that is to show the user his/her final score.
```
console.log(chalk.bgYellow("\nTHE QUIZ ENDED !! FINAL SCORE IS :" + score + " "));
``` 

**## HERE YOU GO , YOUR FIRST CLI APP IS COMPLETE **

If you still find any difficulty or want to checkout my version of "DO YOU KNOW ME".
Checkout the link ( [Click Here ](https://replit.com/@ParulKohli/Level0-Assignment-1?embed=1&output=1) ) and make your version of it .

**CHALLENGE : ADD LEVELS TO YOUR CLI APP .
IF THE PERSON SCORES SUPPOSE 50% OR MORE THEN ONLY ALLOW HIM TO PLAY IN THE NEXT LEVEL . 
**