JavaScript Loop Programs with Solutions

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Print numbers from 1 to 10 (Basic for)

for (let i = 1; i <= 10; i++) {
  console.log(i);
}

2️⃣ Print numbers from 10 to 1 (Reverse loop)

for (let i = 10; i >= 1; i--) {
  console.log(i);
}

3️⃣ Print even numbers (Loop with if)

for (let i = 1; i <= 20; i++) {
  if (i % 2 === 0) {
    console.log(i);
  }
}

4️⃣ Print odd numbers (Loop with if)

for (let i = 1; i <= 20; i++) {
  if (i % 2 !== 0) {
    console.log(i);
  }
}

5️⃣ Sum of numbers from 1 to 10

let sum = 0;for (let i = 1; i <= 10; i++) {
  sum += i;
}console.log(sum);

6️⃣ Multiplication table of 5

for (let i = 1; i <= 10; i++) {
  console.log(`5 x ${i} = ${5 * i}`);
}

7️⃣ Nested loop: Print square pattern

for (let i = 1; i <= 3; i++) {
  let row = "";
  for (let j = 1; j <= 3; j++) {
    row += "* ";
  }
  console.log(row);
}

8️⃣ Nested loop: Number pattern

for (let i = 1; i <= 3; i++) {
  let row = "";
  for (let j = 1; j <= i; j++) {
    row += j + " ";
  }
  console.log(row);
}

9️⃣ while loop: Print 1 to 5

let i = 1;while (i <= 5) {
  console.log(i);
  i++;
}

🔟 while loop: Sum of first 5 numbers

let i = 1;
let sum = 0;while (i <= 5) {
  sum += i;
  i++;
}console.log(sum);

1️⃣1️⃣ do...while: Print 1 to 5

let i = 1;do {
  console.log(i);
  i++;
} while (i <= 5);

1️⃣2️⃣ do...while: Run at least once

let i = 10;do {
  console.log(i);
} while (i < 5);

1️⃣3️⃣ forEach: Print array elements

let arr = [10, 20, 30];arr.forEach(num => console.log(num));

1️⃣4️⃣ forEach: Sum of array

let arr = [1, 2, 3, 4];
let sum = 0;arr.forEach(num => {
  sum += num;
});console.log(sum);

1️⃣5️⃣ Loop through string (characters)

let str = "Hello";for (let char of str) {
  console.log(char);
}

1️⃣6️⃣ Count vowels in a string

let str = "javascript";
let count = 0;for (let char of str) {
  if ("aeiou".includes(char)) {
    count++;
  }
}console.log(count);

1️⃣7️⃣ Loop through array using for

let arr = [5, 10, 15];for (let i = 0; i < arr.length; i++) {
  console.log(arr[i]);
}

1️⃣8️⃣ Find largest number in array

let arr = [10, 5, 20, 8];
let max = arr[0];for (let i = 1; i < arr.length; i++) {
  if (arr[i] > max) {
    max = arr[i];
  }
}console.log(max);

1️⃣9️⃣ Loop through object properties (for...in)

let person = {
  name: "John",
  age: 25,
  city: "Delhi"
};for (let key in person) {
  console.log(key + ": " + person[key]);
}

2️⃣0️⃣ Count properties in an object

let obj = {
  a: 1,
  b: 2,
  c: 3
};let count = 0;for (let key in obj) {
  count++;
}console.log(count);

Beginner Level

  1. Write a JavaScript program to print numbers from 1 to 10 using a for loop.
  2. Write a JavaScript program to print numbers from 10 to 1 in reverse order.
  3. Write a JavaScript program to print all even numbers between 1 and 100.
  4. Write a JavaScript program to print all odd numbers between 1 and 100.
  5. Write a JavaScript program to calculate the sum of numbers from 1 to N.
  6. Write a JavaScript program to calculate the product of numbers from 1 to N.
  7. Write a JavaScript program to print the multiplication table of a given number.
  8. Write a JavaScript program to print the multiplication tables from 1 to 10.
  9. Write a JavaScript program to count the total number of digits in a given number.
  10. Write a JavaScript program to reverse a given number.

Intermediate Level

  1. Write a JavaScript program to check whether a given number is a palindrome.
  2. Write a JavaScript program to find the sum of digits of a given number.
  3. Write a JavaScript program to find the largest digit in a number.
  4. Write a JavaScript program to find the smallest digit in a number.
  5. Write a JavaScript program to calculate the factorial of a number.
  6. Write a JavaScript program to check whether a number is a prime number.
  7. Write a JavaScript program to print all prime numbers between 1 and N.
  8. Write a JavaScript program to count the total number of prime numbers between 1 and N.
  9. Write a JavaScript program to find the sum of all prime numbers between 1 and N.
  10. Write a JavaScript program to print the Fibonacci series up to N terms.

Pattern Programs

  1. Write a JavaScript program to print a right-angled triangle using *.
  2. Write a JavaScript program to print an inverted right-angled triangle.
  3. Write a JavaScript program to print a pyramid pattern using *.
  4. Write a JavaScript program to print an inverted pyramid pattern.
  5. Write a JavaScript program to print a diamond pattern.
  6. Write a JavaScript program to print Floyd’s Triangle.
  7. Write a JavaScript program to print Pascal’s Triangle.
  8. Write a JavaScript program to print a square pattern using *.
  9. Write a JavaScript program to print a hollow square pattern.
  10. Write a JavaScript program to print a hollow pyramid pattern.

Advanced Loop Programs

  1. Write a JavaScript program to find all Armstrong numbers between 1 and N.
  2. Write a JavaScript program to check whether a given number is an Armstrong number.
  3. Write a JavaScript program to find the Greatest Common Divisor (GCD) of two numbers.
  4. Write a JavaScript program to find the Least Common Multiple (LCM) of two numbers.
  5. Write a JavaScript program to convert a decimal number to binary.
  6. Write a JavaScript program to convert a binary number to decimal.
  7. Write a JavaScript program to calculate the power of a number without using built-in methods.
  8. Write a JavaScript program to print all perfect numbers between 1 and N.
  9. Write a JavaScript program to check whether a given number is a perfect number.
  10. Write a JavaScript program to find the sum of all even numbers between 1 and N.

Nested Loop Programs

  1. Write a JavaScript program to print a multiplication table using nested loops.
  2. Write a JavaScript program to print a number triangle pattern.
  3. Write a JavaScript program to print a character triangle pattern.
  4. Write a JavaScript program to print a checkerboard (# and *) pattern.
  5. Write a JavaScript program to print a hollow rectangle using nested loops.
  6. Write a JavaScript program to print an X pattern using *.
  7. Write a JavaScript program to print a butterfly pattern.
  8. Write a JavaScript program to print a sandglass pattern.
  9. Write a JavaScript program to print a zigzag pattern.
  10. Write a JavaScript program to create a simple number guessing game using loops.

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