Hacker Rank - 10 Days of JavaScript Practice

Day -2 JavaScript Practice

Task

Complete the vowelsAndConsonants function in the editor below. It has one parameter, a string, , consisting of lowercase English alphabetic letters (i.e., a through z). The function must do the following:

First, print each vowel in  on a new line. The English vowels are a, e, i, o, and u, and each vowel must be printed in the same order as it appeared in .
Second, print each consonant (i.e., non-vowel) in  on a new line in the same order as it appeared in string.

Solution

function vowelsAndConsonants(s) {
 
const vowels = 'aeiou';
    var consonants = '';
    
    for(var i = 0; i < s.length; i++) {
       if (vowels.includes(s[i])) {
           console.log(s[i]);
       }
       else {
           consonants += s[i] + '\n';
       }
    }
    
    console.log(consonants.trim());
}

Day 1: Functions

Task

Implement a function named factorial that has one parameter: an integer, . It must return the value of  n(i.e.,  factorial).

Solution

function factorial(n){
  var ans=1;
  for(var i=1;i<=n;i++){
    ans=ans*i;

  }
  return ans;
}

function main() {
    const n = +(readLine());
    
    console.log(factorial(n));
}

Day 1: Let and Const

Day 1: Let and Const
Objective
In this challenge, we practice declaring variables using the let and const keywords. Check out the attached tutorial for more details.

Task
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).
Read a number, r, denoting the radius of a circle from stdin.
Use PI and r to calculate the area and perimeter of a circle having radius .
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 <= n <= 100
r is a floating-point number scaled to at most 3 decimal places.

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() {
    const PI=Math.PI;
    let r=parseFloat(readLine());    
    console.log(PI*r*r);
    console.log(2*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.");
    }
}

Day 7: Regular Expressions I

Complete the function in the editor below by returning a RegExp object, , that matches any string  that begins and ends with the same vowel. Recall that the English vowels are a, e, i, o, and u.

Constraints

The length of string  is  s>=3.
String  consists of lowercase letters only (i.e., [a-z]).

'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 regexVar() {
      return new RegExp(/^([aeiou]).*\1$/);
    return re;
}

Hi Saloni,
I have been thinking in a way to solve this problem (regular Expression 1 - Day 7), and I could solve part of this problem. But after a while I found here your solution. Have you any way to explain to me how is that happens / works?

I cannot understand why a two returns function works in this:
function regexVar() {
return new RegExp(/^([aeiou]).*\1$/);
return re;
}