1. Write a JavaScript function to print the “Hello World” message
Function `displayMessage()` prints “Hello World” string using console.log() function.
function displayMessage() {
console.log("Hello World");
}
displayMessage(); //"Hello World"2. Write a function that returns the square of a number
Function `findSquare()` returns the square of the input number which is passed as an argument in the function call.
function findSquare(num) {
return num*num;
}
console.log(findSquare(2)) //4
console.log(findSquare(9)) //81
console.log(findSquare(15)) //2253. Write a function to convert Celsius to Fahrenheit
Function `calFahrenheit()` returns the converted Celsius value to Fahrenheit value based on the formula `(Celsius × 9/5) + 32 = Fahrenheit`
function calFahrenheit(cel) {
return (cel*9/5)+32; //Conversion formula
}
console.log(calFahrenheit(0)) //32
console.log(calFahrenheit(20)) //68
console.log(calFahrenheit(40)) //1044. Write a function to find the area of a given Rectangle
Function `rectangleArea()` returns the rectangle area provided the width and height as the argument.
function rectangleArea(a,b) {
return `The area of rectangle is ${a*b}`;
}
console.log(rectangleArea(10,20)) //The area of rectangle is 200
console.log(rectangleArea(30,30)) //The area of rectangle is 9005. Write a function to find the area and perimeter of a Circle
Function `circleValues()` returns the perimeter and area of the circle provided the radius as an argument for the function call.
function circleValues(rad) {
return `Perimeter: ${2*Math.PI*rad}, Area: ${Math.PI*rad*rad}`;
}
console.log(circleValues(10)) //"Perimeter: 62.83, Area: 314.15"
console.log(circleValues(15)) //"Perimeter: 94.24, Area: 706.85"
console.log(circleValues(25)) //"Perimeter: 157.07, Area: 1963.49"6. Write a function to reverse a number
Function `reverseNum()` returns the reversed number for the given argument number value.
function reverseNum(num) {
var reverse = 0;
while(num != 0)
{
reverse = reverse * 10;
reverse = reverse + num%10;
num = Math.trunc(num/10); // Remove decimal places
}
return reverse;
}
console.log(reverseNum(123)) //321
console.log(reverseNum(5872)) //27857. Count number of Vowels in String
Function `countVowel()` returns the number of vowels in input string. Learn more about JavaScript String methods from javatpoint.com/javascript-string.
function countVowel(str) {
var count = 0;
str=str.toLowerCase();
for(var i=0;i<str.length;i++){
if(str.charAt(i)=="a"||str.charAt(i)=="e"||str.charAt(i)=="i"||
str.charAt(i)=="o"||str.charAt(i)=="u"){
count++; //Increment vowel count
}
}
return count;
}
console.log(countVowel("Hello")) //2
console.log(countVowel("Umbrella")) //38. Flatten array of arrays using JavaScript reduce
Function `flattenArr()` flattens a 2D array by combining each sub array into 1D array by using JavaScript reduce.
function flattenArr(arr) {
return arr.reduce((result, array) => result.concat(array));
}
console.log(flattenArr([[1, 2, 3], [4, 5, 6], [7, 8, 9]]))
// [1, 2, 3, 4, 5, 6, 7, 8, 9]9. Write a function to check if an input string is a palindrome
Function `checkPalindrome()` return a boolean value based on whether the input string is palindrome or not.
function checkPalindrome(str) {
for(var i=0;i<str.length;i++){
if(str.charAt(i)!=str.charAt(str.length-i-1)){ // Comparison fail
return false;
}
}
return true;
}
console.log(findPalindrome("bannana")) //false
console.log(findPalindrome("racecar")) //true
console.log(findPalindrome("madam")) //true10. Write a function to calculate simple interest based on the principle amount
Function `simpleInt()` returns a final amount based on the simple interest formula provided principal amount, rate of interest per year, and time on a yearly basis.
function simpleInt(principle, rate, time) {
var finalAmt=principle + principle*time*rate;
return finalAmt;
}
console.log(simpleInt(20000,5,2)) //220000
console.log(simpleInt(150000,25,1)) //390000011. Write a function to calculate compound interest based on the principle amount
Function `compoundInt()` returns a final amount based on the compound interest formula provided principal amount, rate of interest per year, time on a yearly basis, and n as the number of times that interest is compounded per unit time.
function compoundInt(principle, rate, time, n) {
var interest = principle * (Math.pow((1 + (rate / n)), (n * time)));
return principle + interest;
}
console.log(compoundInt(20000,5,2,2)) //3021250
console.log(compoundInt(150000,25,1,2)) //2748750012. Write a function to generate a random number
Function `genRandom()` return a generated random integer number between the provided start and end range.
function genRandom(start, end) {
return Math.floor(Math.random() * end) + start
}
console.log(genRandom(1,10)) // random int between 1 to 10
console.log(genRandom(80,90)) // random int between 80 to 9013. Write a function to find Factorial of a number
Function `getFactorial()` return the factorial of a number using the formula `n*(n-1)*(n-2)*…` .
function getFactorial(num) {
if(num==1){
return 1; // Termination condition
}
if(num==0 || num<0){
return 0; // Termination condition
}
return num*getFactorial(num-1);
}
console.log(getFactorial(5)) // 120
console.log(getFactorial(12)) // 47900160014. Write a function to add unlimited numbers
Function `addNumber()` return the sum of all the number passed as arguments of the function.
function addNumber(...args) {
return args.reduce((total,num) => total+num); //Add numbers
}
console.log(addNumber(2,4,5)) // 11
console.log(addNumber(10,45,34,130)) // 21915. Write a function to combine unlimited arrays
Function `addArrays()` return the concatenated array by combining all the arrays passed as an argument of the function.
function addArrays(...args) {
return args.reduce((total,arr)=>total.concat(arr));
}
console.log(addArrays([2,3,4],[6,4,9],[34,6,4]))
// [2, 3, 4, 6, 4, 9, 34, 6, 4]16. Write a function to find the count of a letter in a string
Function `letterCount()` return the count of letter in a given string.
function letterCount(str, c) {
var count=0;
str=str.toLowerCase(); //Case insensitive
for(var i=0;i<str.length;i++){
if(str.charAt(i)==c){
count++; //Increment count
}
}
return count;
}
console.log(letterCount("Connect",'c')) // 2
console.log(letterCount("first person",'s')) // 217. Write a function to check if a number is Prime
Function `checkPrime()` return Boolean value based on whether the number is Prime or not.
function checkPrime(num, div=2) {
// Base case
if (num <= 2){
return (num == 2) ? true : false;
}
// No Divisor case
if (div * div > num){
return true;
}
// Number is not prime if divisible
if (num % div == 0){
return false;
}
// Recursive call with next divisor
return checkPrime(num, div+1);
}
console.log(checkPrime(27)) // false
console.log(checkPrime(19)) // trueJavaScript beginner exercises
