Dive Into the World of JavaScript Loops

JavaScript Loops

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Exercise 1: Basic For Loop

Problem: Print numbers 1 through 10 using a for loop.

Explanation: This exercise demonstrates the basic structure of a for loop, which includes initialization, condition, and increment sections.

Code:

for (let i = 1; i <= 10; i++) {

 console.log(i);

}

Exercise 2: For Loop Array Iteration

Problem: Iterate over an array containing ["apple", "banana", "cherry"] and print each fruit.

Explanation: This exercise shows how to use a for loop to iterate through an array's elements.

Code:

let fruits = ["apple", "banana", "cherry"];

for (let i = 0; i < fruits.length; i++) {

 console.log(fruits[i]);

}

Exercise 3: While Loop Basics

Problem: Use a while loop to print numbers from 5 to 15.

Explanation: This exercise introduces the while loop, which continues to execute a block of code as long as a specified condition is true.

Code:

let i = 5;

while (i <= 15) {

 console.log(i);

 i++;

}

Exercise 4: Do-While Loop

Problem: Implement a do-while loop to print "Hello, World!" 5 times.

Explanation: Unlike the while loop, a do-while loop will execute the block of code once before checking if the condition is true, then it will repeat the loop as long as the condition is true.

Code:

let count = 0;

do {

 console.log("Hello, World!");

 count++;

} while (count < 5);

Exercise 5: Breaking Out of a Loop

Problem: Use a for loop to print numbers from 1 to 10. Exit the loop when the loop index is 6 using the break statement.

Explanation: The break statement can be used to exit a loop before it has looped through all items.

Code:

for (let i = 1; i <= 10; i++) {

 if (i === 6) {

 break;

 }

 console.log(i);

}

Exercise 6: Continue in a Loop

Problem: Use a for loop to print all numbers from 1 to 10 except for 4.

Explanation: The continue statement skips one iteration in the loop.

Code:

for (let i = 1; i <= 10; i++) {

 if (i === 4) {

 continue;

 }

 console.log(i);

}

Exercise 7: Nested Loops

Problem: Print a 5x5 grid of asterisks using nested for loops.

Explanation: This exercise demonstrates using one loop inside another to generate a grid pattern.

Code:

for (let i = 0; i < 5; i++) {

 let row = '';

 for (let j = 0; j < 5; j++) {

 row += '* ';

 }

 console.log(row.trim());

}

Exercise 8: Looping Backwards

Problem: Use a for loop to print the numbers 10 down to 1 in reverse order.

Explanation: Looping backwards requires setting the loop's starting condition to the maximum and decrementing the loop variable.

Code:

for (let i = 10; i > 0; i--) {

 console.log(i);

}

Exercise 9: Sum Numbers

Problem: Write a loop that sums numbers from 1 to 100.

Explanation: This shows how to accumulate a total within a loop.

Code:

let sum = 0;

for (let i = 1; i <= 100; i++) {

 sum += i;

}

console.log(sum);

Exercise 10: Factorial Calculation

Problem: Write a function that calculates the factorial of a number using a loop.

Explanation: This demonstrates using a loop within a function to perform a calculation that requires repetitive operations.

Code:

function factorial(n) {

 let result = 1;

 for (let i = 2; i <= n; i++) {

 result *= i;

 }

 return result;

}

console.log(factorial(5)); // Outputs: 120