1
Hello World
console.log('Hello World');
2
Add Two Numbers
const num1 = 5;
const num2 = 3;
// add two numbers
const sum = num1 + num2;
// display the sum
console.log('The sum of ' + num1 + ' and ' + num2 + ' is: ' + sum);
3
Square Root of a Number
// take the input from the user
const number = prompt('Enter the number: ');
const result = Math.sqrt(number);
console.log(`The square root of ${number} is ${result}`);
4
Traiangle Area When Base and Height is Known
const baseValue = prompt('Enter the base of a triangle: ');
const heightValue = prompt('Enter the height of a triangle: ');
// calculate the area
const areaValue = (baseValue * heightValue) / 2;
console.log(
`The area of the triangle is ${areaValue}`
);
5
swap two variables
//JavaScript program to swap two variables
//take input from the users
let a = prompt('Enter the first variable: ');
let b = prompt('Enter the second variable: ');
//create a temporary variable
let temp;
//swap variables
temp = a;
a = b;
b = temp;
console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);
6
Convert Kilometers to Miles
// taking kilometers input from the user
const kilometers = prompt("Enter value in kilometers: ")
// conversion factor
const factor = 0.621371
// calculate miles
const miles = kilometers * factor
console.log(`${kilometers} kilometers is equal to ${miles} miles.`);
7
convert celsius to fahrenheit
// program to convert celsius to fahrenheit
// ask the celsius value to the user
const celsius = prompt("Enter a celsius value: ");
// calculate fahrenheit
const fahrenheit = (celsius * 1.8) + 32
// display the result
console.log(`${celsius} degree celsius is equal to ${fahrenheit} degree fahrenheit.`);
8
include constants
// program to include constants
const a = 5;
console.log(a);
// constants are block-scoped
{
const a = 50;
console.log(a);
}
console.log(a);
const arr = ['work', 'exercise', 'eat'];
console.log(arr);
// add elements to arr array
arr[3] = 'hello';
console.log(arr);
// the following code gives error
// changing the value of a throws an error
// uncomment to verify
// a = 8;
// throws an error
// const x;
9
generating a random number
// generating a random number
const a = Math.random();
console.log(a);
10
positive, negative or zero
// program that checks if the number is positive, negative or zero
// input from the user
const number = parseInt(prompt("Enter a number: "));
// check if number is greater than 0
if (number > 0) {
console.log("The number is positive");
}
// check if number is 0
else if (number == 0) {
console.log("The number is zero");
}
// if number is less than 0
else {
console.log("The number is negative");
}
11
number is even or odd
// program to check if the number is even or odd
// take input from the user
const number = prompt("Enter a number: ");
//check if the number is even
if(number % 2 == 0) {
console.log("The number is even.");
}
// if the number is odd
else {
console.log("The number is odd.");
}
12
largest among three numbers
// program to find the largest among three numbers
// take input from the user
const num1 = parseFloat(prompt("Enter first number: "));
const num2 = parseFloat(prompt("Enter second number: "));
const num3 = parseFloat(prompt("Enter third number: "));
let largest;
// check the condition
if(num1 >= num2 && num1 >= num3) {
largest = num1;
}
else if (num2 >= num1 && num2 >= num3) {
largest = num2;
}
else {
largest = num3;
}
// display the result
console.log("The largest number is " + largest);
13
prime or not
// program to check if a number is prime or not
// take input from the user
const number = parseInt(prompt("Enter a positive number: "));
let isPrime = true;
// check if number is equal to 1
if (number === 1) {
console.log("1 is neither prime nor composite number.");
}
// check if number is greater than 1
else if (number > 1) {
// looping through 2 to number-1
for (let i = 2; i < number; i++) {
if (number % i == 0) {
isPrime = false;
break;
}
}
if (isPrime) {
console.log(`${number} is a prime number`);
} else {
console.log(`${number} is a not prime number`);
}
}
// check if number is less than 1
else {
console.log("The number is not a prime number.");
}
14
factorial of a number
// program to find the factorial of a number
// take input from the user
const number = parseInt(prompt('Enter a positive integer: '));
// checking if number is negative
if (number < 0) {
console.log('Error! Factorial for negative number does not exist.');
}
// if number is 0
else if (number === 0) {
console.log(`The factorial of ${number} is 1.`);
}
// if number is positive
else {
let fact = 1;
for (i = 1; i <= number; i++) {
fact *= i;
}
console.log(`The factorial of ${number} is ${fact}.`);
}
15
multiplication table
// program to generate a multiplication table
// take input from the user
const number = parseInt(prompt('Enter an integer: '));
//creating a multiplication table
for(let i = 1; i <= 10; i++) {
// multiply i with number
const result = i * number;
// display the result
console.log(`${number} * ${i} = ${result}`);
}
16
fibonacci series up to n terms
// program to generate fibonacci series up to n terms
// take input from the user
const number = parseInt(prompt('Enter the number of terms: '));
let n1 = 0, n2 = 1, nextTerm;
console.log('Fibonacci Series:');
for (let i = 1; i <= number; i++) {
console.log(n1);
nextTerm = n1 + n2;
n1 = n2;
n2 = nextTerm;
}
17
Armstrong number
// program to check an Armstrong number of three digits
let sum = 0;
const number = prompt('Enter a three-digit positive integer: ');
// create a temporary variable
let temp = number;
while (temp > 0) {
// finding the one's digit
let remainder = temp % 10;
sum += remainder * remainder * remainder;
// removing last digit from the number
temp = parseInt(temp / 10); // convert float into integer
}
// check the condition
if (sum == number) {
console.log(`${number} is an Armstrong number`);
}
else {
console.log(`${number} is not an Armstrong number.`);
}
18
Armstrong number between intervals
// program to find Armstrong number between intervals
// take an input
const lowNumber = parseInt(prompt('Enter a positive low integer value: '));
const highNumber = parseInt(prompt('Enter a positive high integer value: '));
console.log ('Armstrong Numbers:');
// looping through lowNumber to highNumber
for (let i = lowNumber; i <= highNumber; i++) {
// converting number to string
let numberOfDigits = i.toString().length;
let sum = 0;
// create a temporary variable
let temp = i;
/* loop through a number to find if
a number is an Armstrong number */
while (temp > 0) {
let remainder = temp % 10;
sum += remainder ** numberOfDigits;
// removing last digit from the number
temp = parseInt(temp / 10); // convert float into integer
}
if (sum == i) {
console.log(i);
}
}
19
simple calculator
// program for a simple calculator
// take the operator input
const operator = prompt('Enter operator ( either +, -, * or / ): ');
// take the operand input
const number1 = parseFloat(prompt('Enter first number: '));
const number2 = parseFloat(prompt('Enter second number: '));
let result;
// using if...else if... else
if (operator == '+') {
result = number1 + number2;
}
else if (operator == '-') {
result = number1 - number2;
}
else if (operator == '*') {
result = number1 * number2;
}
else {
result = number1 / number2;
}
// display the result
console.log(`${number1} ${operator} ${number2} = ${result}`);
20
largest among
// program to find the largest among three numbers
// take input from the user
const num1 = parseFloat(prompt("Enter first number: "));
const num2 = parseFloat(prompt("Enter second number: "));
const num3 = parseFloat(prompt("Enter third number: "));
let largest;
// check the condition
if(num1 >= num2 && num1 >= num3) {
largest = num1;
}
else if (num2 >= num1 && num2 >= num3) {
largest = num2;
}
else {
largest = num3;
}
// display the result
console.log("The largest number is " + largest);
21
sum of natural numbers
// program to display the sum of natural numbers
// take input from the user
const number = parseInt(prompt('Enter a positive integer: '));
let sum = 0;
// looping from i = 1 to number
// in each iteration, i is increased by 1
for (let i = 1; i <= number; i++) {
sum += i;
}
console.log('The sum of natural numbers:', sum);
22
last digit of three numbers is same
/* program to check whether the last digit of three
numbers is same */
// take input
const a = prompt('Enter a first integer: ');
const b = prompt('Enter a second integer: ');
const c = prompt('Enter a third integer: ');
// find the last digit
const result1 = a % 10;
const result2 = b % 10;
const result3 = c % 10;
// compare the last digits
if(result1 == result2 && result1 == result3) {
console.log(`${a}, ${b} and ${c} have the same last digit.`);
}
else {
console.log(`${a}, ${b} and ${c} have different last digit.`);
}
23
HCF or GCD
// program to find the HCF or GCD of two integers
let hcf;
// take input
const number1 = prompt('Enter a first positive integer: ');
const number2 = prompt('Enter a second positive integer: ');
// looping from 1 to number1 and number2
for (let i = 1; i <= number1 && i <= number2; i++) {
// check if is factor of both integers
if( number1 % i == 0 && number2 % i == 0) {
hcf = i;
}
}
// display the hcf
console.log(`HCF of ${number1} and ${number2} is ${hcf}.`);
24
LCM
// program to find the LCM of two integers
// take input
const num1 = prompt('Enter a first positive integer: ');
const num2 = prompt('Enter a second positive integer: ');
// higher number among number1 and number2 is stored in min
let min = (num1 > num2) ? num1 : num2;
// while loop
while (true) {
if (min % num1 == 0 && min % num2 == 0) {
console.log(`The LCM of ${num1} and ${num2} is ${min}`);
break;
}
min++;
}
25
factors of an integer
// program to find the factors of an integer
// take input
const num = prompt('Enter a positive number: ');
console.log(`The factors of ${num} is:`);
// looping through 1 to num
for(let i = 1; i <= num; i++) {
// check if number is a factor
if(num % i == 0) {
console.log(i);
}
}
26
sum of natural numbers
// program to find the sum of natural numbers using recursion
function sum(num) {
if(num > 0) {
return num + sum(num - 1);
}
else {
return num;
}
}
// take input from the user
const number = parseInt(prompt('Enter a positive integer: '));
const result = sum(number);
// display the result
console.log(`The sum is ${result}`);
27
guess a number
// program where the user has to guess a number generated by a program
function guessNumber() {
// generating a random integer from 1 to 10
const random = Math.floor(Math.random() * 10) + 1;
// take input from the user
let number = parseInt(prompt('Guess a number from 1 to 10: '));
// take the input until the guess is correct
while(number !== random) {
number = parseInt(prompt('Guess a number from 1 to 10: '));
}
// check if the guess is correct
if(number == random) {
console.log('You guessed the correct number.');
}
}
// call the function
guessNumber();
28
shuffle the deck of cards
// program to shuffle the deck of cards
// declare card elements
const suits = ["Spades", "Diamonds", "Club", "Heart"];
const values = [
"Ace",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"Jack",
"Queen",
"King",
];
// empty array to contain cards
let deck = [];
// create a deck of cards
for (let i = 0; i < suits.length; i++) {
for (let x = 0; x < values.length; x++) {
let card = { Value: values[x], Suit: suits[i] };
deck.push(card);
}
}
// shuffle the cards
for (let i = deck.length - 1; i > 0; i--) {
let j = Math.floor(Math.random() * i);
let temp = deck[i];
deck[i] = deck[j];
deck[j] = temp;
}
console.log('The first five cards are:');
// display 5 results
for (let i = 0; i < 5; i++) {
console.log(`${deck[i].Value} of ${deck[i].Suit}`)
}
29
factorial of a number
// program to find the factorial of a number
function factorial(x) {
// if number is 0
if (x == 0) {
return 1;
}
// if number is positive
else {
return x * factorial(x - 1);
}
}
// take input from the user
const num = prompt('Enter a positive number: ');
// calling factorial() if num is positive
if (num >= 0) {
const result = factorial(num);
console.log(`The factorial of ${num} is ${result}`);
}
else {
console.log('Enter a positive number.');
}
30
convert decimal to binary
// program to convert decimal to binary
function convertToBinary(x) {
let bin = 0;
let rem, i = 1, step = 1;
while (x != 0) {
rem = x % 2;
console.log(
`Step ${step++}: ${x}/2, Remainder = ${rem}, Quotient = ${parseInt(x/2)}`
);
x = parseInt(x / 2);
bin = bin + rem * i;
i = i * 10;
}
console.log(`Binary: ${bin}`);
}
// take input
let number = prompt('Enter a decimal number: ');
convertToBinary(number);
31
ASCII
// program to find the ASCII value of a character
// take input from the user
const string = prompt('Enter a character: ');
// convert into ASCII value
const result = string.charCodeAt(0);
console.log(`The ASCII value is: ${result}`);
32
palindrome or not
// program to check if the string is palindrome or not
function checkPalindrome(string) {
// find the length of a string
const len = string.length;
// loop through half of the string
for (let i = 0; i < len / 2; i++) {
// check if first and last string are same
if (string[i] !== string[len - 1 - i]) {
return 'It is not a palindrome';
}
}
return 'It is a palindrome';
}
// take input
const string = prompt('Enter a string: ');
// call the function
const value = checkPalindrome(string);
console.log(value);
33
alphabetical order
// program to sort words in alphabetical order
// take input
const string = prompt('Enter a sentence: ');
// converting to an array
const words = string.split(' ');
// sort the array elements
words.sort();
// display the sorted words
console.log('The sorted words are:');
for (const element of words) {
console.log(element);
}
34
replace a character
// program to replace a character of a string
const string = 'Mr Red has a red house and a red car';
// replace the characters
const newText = string.replace('red', 'blue');
// display the result
console.log(newText);
35
reverse a string
// program to reverse a string
function reverseString(str) {
// empty string
let newString = "";
for (let i = str.length - 1; i >= 0; i--) {
newString += str[i];
}
return newString;
}
// take input from the user
const string = prompt('Enter a string: ');
const result = reverseString(string);
console.log(result);
36
create JavaScript object
// program to create JavaScript object using object literal
const person = {
name: 'John',
age: 20,
hobbies: ['reading', 'games', 'coding'],
greet: function() {
console.log('Hello everyone.');
},
score: {
maths: 90,
science: 80
}
};
console.log(typeof person); // object
// accessing the object value
console.log(person.name);
console.log(person.hobbies[0]);
person.greet();
console.log(person.score.maths);
37
number of occurrence of a character
// program to check the number of occurrence of a character
function countString(str, letter) {
let count = 0;
// looping through the items
for (let i = 0; i < str.length; i++) {
// check if the character is at that position
if (str.charAt(i) == letter) {
count += 1;
}
}
return count;
}
// take input from the user
const string = prompt('Enter a string: ');
const letterToCheck = prompt('Enter a letter to check: ');
//passing parameters and calling the function
const result = countString(string, letterToCheck);
// displaying the result
console.log(result);
38
convert first letter uppercase
// program to convert first letter of a string to uppercase
function capitalizeFirstLetter(str) {
// converting first letter to uppercase
const capitalized = str.charAt(0).toUpperCase() + str.slice(1);
return capitalized;
}
// take input
const string = prompt('Enter a string: ');
const result = capitalizeFirstLetter(string);
console.log(result);
39
number of vowels
// program to count the number of vowels in a string
function countVowel(str) {
// find the count of vowels
const count = str.match(/[aeiou]/gi).length;
// return number of vowels
return count;
}
// take input
const string = prompt('Enter a string: ');
const result = countVowel(string);
console.log(result);
40
remove a property
// program to remove a property from an object
// creating an object
const student = {
name: 'John',
age: 20,
hobbies: ['reading', 'games', 'coding'],
greet: function() {
console.log('Hello everyone.');
},
score: {
maths: 90,
science: 80
}
};
// deleting a property from an object
delete student.greet;
delete student['score'];
console.log(student);
41
check if a string
// program to check if a string starts with 'S' and ends with 'G'
function checkString(str) {
// check if the string starts with S and ends with G
if(str.startsWith('S') && str.endsWith('G')) {
console.log('The string starts with S and ends with G');
}
else if(str.startsWith('S')) {
console.log('The string starts with S but does not end with G');
}
else if(str.endsWith('G')) {
console.log('The string starts does not with S but end with G');
}
else {
console.log('The string does not start with S and does not end with G');
}
}
// take input
let string = prompt('Enter a string: ');
checkString(string);
42
key exists
// program to check if a key exists
const person = {
id: 1,
name: 'John',
age: 23
}
// check if key exists
const hasKey = 'name' in person;
if(hasKey) {
console.log('The key exists.');
}
else {
console.log('The key does not exist.');
}
43
clone the object
// program to clone the object
// declaring object
const person = {
name: 'John',
age: 21,
}
// cloning the object
const clonePerson = Object.assign({}, person);
console.log(clonePerson);
// changing the value of clonePerson
clonePerson.name = 'Peter';
console.log(clonePerson.name);
console.log(person.name);
44
loop through an object
// program to loop through an object using for...in loop
const student = {
name: 'John',
age: 20,
hobbies: ['reading', 'games', 'coding'],
};
// using for...in
for (let key in student) {
let value;
// get the value
value = student[key];
console.log(key + " - " + value);
}
45
merge property
// program to merge property of two objects
// object 1
const person = {
name: 'Jack',
age:26
}
// object 2
const student = {
gender: 'male'
}
// merge two objects
const newObj = Object.assign(person, student);
console.log(newObj);
46
number of keys/properties in an object
// program to count the number of keys/properties in an object
const student = {
name: 'John',
age: 20,
hobbies: ['reading', 'games', 'coding'],
};
let count = 0;
// loop through each key/value
for(let key in student) {
// increase the count
++count;
}
console.log(count);
47
add a key/value pair
// program to add a key/value pair to an object
const person = {
name: 'Monica',
age: 22,
gender: 'female'
}
// add a key/value pair
person.height = 5.4;
console.log(person);
48
replace all occurrence
// program to replace all occurrence of a string
const string = 'Mr Red has a red house and a red car';
// regex expression
const regex = /red/gi;
// replace the characters
const newText = string.replace(regex, 'blue');
// display the result
console.log(newText);
49
multiline strings
// program to create a multiline strings
// using the + operator
const message = 'This is a long message\n' +
'that spans across multiple lines\n' +
'in the code.'
console.log(message);
50
format numbers as currency string
// program to format numbers as currency string
const formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD'
});
formatter.format(2500);
51
format numbers
// program to format numbers as currency string
const formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD'
});
formatter.format(2500);
52
generate random strings
// program to generate random strings
// declare all characters
const characters ='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
function generateString(length) {
let result = ' ';
const charactersLength = characters.length;
for ( let i = 0; i < length; i++ ) {
result += characters.charAt(Math.floor(Math.random() * charactersLength));
}
return result;
}
console.log(generateString(5));
53
starts with another string
// program to check if a string starts with another string
const string = 'hello world';
const toCheckString = 'he';
if(string.startsWith(toCheckString)) {
console.warn('The string starts with "he".');
}
else {
console.warn(`The string does not starts with "he".`);
}
54
trim a string
// program to trim a string
const string = ' Hello World ';
const result = string.trim();
console.log(result);
55
string contains a substring
// program to check if a string contains a substring
// take input
const str = prompt('Enter a string:');
const checkString = prompt('Enter a string that you want to check:');
// check if string contains a substring
if(str.includes(checkString)) {
console.log(`The string contains ${checkString}`);
} else {
console.log(`The string does not contain ${checkString}`);
}
56
perform string comparison
// js program to perform string comparison
const string1 = 'JavaScript Program';
const string2 = 'javascript program';
// compare both strings
const result = string1.toUpperCase() === string2.toUpperCase();
if(result) {
console.log('The strings are similar.');
} else {
console.log('The strings are not similar.');
}
57
encode a string to Base64
// program to encode a string to Base64
// defining the string
const str = "Learning JavaScript";
// encoding the string
const result = window.btoa(str);
console.log(result);
// decoding the string
const result1 = window.atob(result);
console.log(result1);
58
replace all instances
// program to replace all instances of a character in a string
const string = 'Learning JavaScript Program';
const result = string.replace(/a/g, "A");
console.log(result);
59
date and time
// program to display the date and time
// get date and time
const date = new Date(2017, 2, 12, 9, 25, 30);
// get the date as a string
const n = date.toDateString();
// get the time as a string
const time = date.toLocaleTimeString();
// display date
console.log('Date: ' + n);
// display time
console.log('Time: ' + time);
60
check leap year
// program to check leap year
function checkLeapYear(year) {
//three conditions to find out the leap year
if ((0 == year % 4) && (0 != year % 100) || (0 == year % 400)) {
console.log(year + ' is a leap year');
} else {
console.log(year + ' is not a leap year');
}
}
// take input
const year = prompt('Enter a year:');
checkLeapYear(year);
61
format the date
// program to format the date
// get current date
let currentDate = new Date();
// get the day from the date
let day = currentDate.getDate();
// get the month from the date
// + 1 because month starts from 0
let month = currentDate.getMonth() + 1;
// get the year from the date
let year = currentDate.getFullYear();
// if day is less than 10, add 0 to make consistent format
if (day < 10) {
day = '0' + day;
}
// if month is less than 10, add 0
if (month < 10) {
month = '0' + month;
}
// display in various formats
const formattedDate1 = month + '/' + day + '/' + year;
console.log(formattedDate1);
const formattedDate2 = month + '-' + day + '-' + year;
console.log(formattedDate2);
const formattedDate3 = day + '-' + month + '-' + year;
console.log(formattedDate3);
const formattedDate4 = day + '/' + month + '/' + year;
console.log(formattedDate4);
62
display the date
// program to display the date
// get local machine date time
const date = new Date();
// get the date as a string
const n = date.toDateString();
// get the time as a string
const time = date.toLocaleTimeString();
// display date
console.log('Date: ' + n);
// display time
console.log('Time: ' + time);
63
compare value of two dates
// program to compare value of two dates
// create two dates
const d1 = new Date();
const d2 = new Date();
// comparisons
const compare1 = d1 < d2;
console.log(compare1);
const compare2 = d1 > d2;
console.log(compare2);
const compare3 = d1 <= d2;
console.log(compare3);
const compare4 = d1 >= d2;
console.log(compare4);
const compare5 = d1.getTime() === d2.getTime();
console.log(compare5);
const compare6 = d1.getTime() !== d2.getTime();
console.log(compare6);
64
remove item from an array
// program to remove item from an array
function removeItemFromArray(array, n) {
const newArray = [];
for ( let i = 0; i < array.length; i++) {
if(array[i] !== n) {
newArray.push(array[i]);
}
}
return newArray;
}
const result = removeItemFromArray([1, 2, 3 , 4 , 5], 2);
console.log(result);
65
insert an item into an array
// program to insert an item at a specific index into an array
function insertElement() {
let array = [1, 2, 3, 4, 5];
// index to add to
let index = 3;
// element that you want to add
let element = 8;
array.splice(index, 0, element);
console.log(array);
}
insertElement();
66
check if an object is array
// program to check if an object is an array
function checkObject(arr) {
// check if arr is array
const result = Array.isArray(arr);
if(result) {
console.log(`[${arr}] is an array.`);
}
else {
console.log(`${arr} is not an array.`);
}
}
const array = [1, 2, 3];
// call the function
checkObject(array);
