Day 1: Let and Const | 10 Days of JavaScript | HackerRank Solution

Hello coders, today we are going to solve Day 1: Let and Const HackerRank Solution which is a part of 10 Days of JavaScript Series.

Objective

In this challenge, we practice declaring variables using the let and const keywords. Check out the attached tutorial for more details.

Task

1. Declare a constant variable, PI, and assign it the value Math.PI. You will not pass this challenge unless the variable is declared as a constant and named PI (uppercase).
2. Read a number, r, denoting the radius of a circle from stdin.
3. Use PI and r to calculate the area and perimeter of a circle having radius .
4. Print area as the first line of output and print perimeter as the second line of output.

Input Format

A single integer, r, denoting the radius of a circle.

Constraints

• 0 < r <= 100
• r  is a floating-point number scaled to at most 3 decimal places.

Output Format

Print the following two lines:

1. On the first line, print the area of the circle having radius r.
2. On the second line, print the perimeter of the circle having radius r.

Sample Input 0

2.6

Sample Output 0

21.237166338267002
16.336281798666924

Explanation 0

Given the radius r = 2.6, we calculate the following:

• area = π * r^2 = 21.237166338267002
• perimeter = 2 * π * r = 16.336281798666924

We then print area as our first line of output and perimeter as our second line of output.

Solution – Day 1: Let and Const

'use strict';

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', _ => {
    inputString = inputString.trim().split('\n').map(string => {
        return string.trim();
    });
    
    main();    
});

function readLine() {
    return inputString[currentLine++];
}

function main() {
    // Write your code here. Read input using 'readLine()' and print output using 'console.log()'.
    var r = readLine();
    // Print the area of the circle:
    console.log(Math.PI * r * r);
    // Print the perimeter of the circle:
    console.log(2 * Math.PI * r);

    try {    
        // Attempt to redefine the value of constant variable PI
        PI = 0;
        // Attempt to print the value of PI
        console.log(PI);
    } catch(error) {
        console.error("You correctly declared 'PI' as a constant.");
    }
}

Disclaimer: The above Problem (Let and Const) is generated by Hacker Rank but the Solution is provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.