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🔁 JavaScript Loop Practice Exercises

📑 Table of Contents

Exercise 1: Print Numbers from 1 to 10 — ⭐☆☆ (Easy)

Use a for loop to print numbers from 1 to 10. 
for (let i = 1; i <= 10; i++) {
          console.log(i);
        }

Exercise 2: Print Even Numbers from 1 to 20 — ⭐☆☆ (Easy)

Use a for loop to print even numbers from 1 to 20. 
for (let i = 2; i <= 20; i += 2) {
          console.log(i);
        }

Exercise 3: Calculate Sum from 1 to 100 using while — ⭐⭐☆ (Medium)

Use a while loop to calculate the sum of numbers from 1 to 100. 
let sum = 0, i = 1;
        while (i <= 100) {
          sum += i;
          i++;
        }
        console.log(sum);

Exercise 4: Multiplication Table using do...while — ⭐⭐☆ (Medium)

Use a do...while loop to print the multiplication table of 5. 
let i = 1;
        const n = 5;
        do {
          console.log(`${n} x ${i} = ${n * i}`);
          i++;
        } while (i <= 10);

Exercise 5: Loop through Object using for...in — ⭐⭐☆ (Medium)

Use a for...in loop to print keys and values of an object. 
const person = { name: "Ali", age: 25, city: "Colombo" };
        for (let key in person) {
          console.log(key + ": " + person[key]);
        }

Exercise 6: Loop through Array using for...of — ⭐⭐☆ (Medium)

Use a for...of loop to print all elements of an array. 
const fruits = ["apple", "banana", "mango"];
        for (let fruit of fruits) {
          console.log(fruit);
        }

Exercise 7: Skip Odd Numbers using continue — ⭐⭐☆ (Medium)

Use a for loop and continue to skip odd numbers. 
for (let i = 1; i <= 10; i++) {
          if (i % 2 !== 0) continue;
          console.log(i);
        }

Exercise 8: Stop Loop at First Negative using break — ⭐⭐⭐ (Hard)

Loop through an array and stop at the first negative number using break. 
const nums = [10, 15, -5, 20];
        for (let num of nums) {
          if (num < 0) break;
          console.log(num);
        }

Exercise 9: Nested Loop Pattern Printing — ⭐⭐⭐ (Hard)

Use nested for loops to print the following pattern:
*
**
***
****
***** 
for (let i = 1; i <= 5; i++) {
          let row = "";
          for (let j = 1; j <= i; j++) {
            row += "*";
          }
          console.log(row);
        }

Exercise 10: FizzBuzz — ⭐⭐⭐ (Hard)

Print numbers from 1 to 50. For multiples of 3, print Fizz; for multiples of 5, print Buzz; for both, print FizzBuzz. 
for (let i = 1; i <= 50; i++) {
          if (i % 3 === 0 && i % 5 === 0) console.log("FizzBuzz");
          else if (i % 3 === 0) console.log("Fizz");
          else if (i % 5 === 0) console.log("Buzz");
          else console.log(i);
        }