HackerRank 10 Days Of Javascript Solution:-Day 1: Let and Const

Problem:-

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, , 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, , denoting the radius of a circle from stdin.
3. Use  and  to calculate the  and  of a circle having radius .
4. Print  as the first line of output and print  as the second line of output.

Input Format

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

Constraints

•  is a floating-point number scaled to at most  decimal places.

Output Format

Print the following two lines:

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

Sample Input 0

2.6

Sample Output 0

21.237166338267002
16.336281798666924

Explanation 0

Given the radius , we calculate the following:

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

Solution:-

'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() {

let r = readLine();

const PI = Math.PI;

// Print the area of the circle:

console.log(PI * r * r);

// Print the perimeter of the circle:

console.log(PI * 2 * 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.");

}

}