JavaScript

The for loop is used to repeat a block of code a specific number of times. It is commonly used when you know how many times you want to run the code.

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✅ Syntax

for (initialization; condition; increment) {
  // Code to execute on each loop
}

• Initialization: runs once, before the loop starts.
• Condition: checked before every loop iteration.
• Increment/Decrement: updates the loop variable after each iteration.

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📌 Example: Counting 1 to 5

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

Output:

1
2
3
4
5

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🔄 Loop Breakdown

for (let i = 0; i < 3; i++) {
  console.log("Looping!");
}

What happens here:

1. let i = 0 → Start with i = 0.
2. i < 3 → Loop runs while i is less than 3.
3. i++ → After each loop, increase i by 1.
4. Repeats 3 times: when i is 0, 1, 2.

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❌ Loop Without break

If you forget to update your variable or use a wrong condition, it can cause an infinite loop:

for (let i = 0; i >= 0; i++) {
  console.log("Oops! Infinite loop!");
}

Always make sure your loop condition will eventually become false!

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🔁 Looping Through an Array

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

for (let i = 0; i < fruits.length; i++) {
  console.log(fruits[i]);
}

Output:

apple
banana
cherry

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🔁 Reverse Loop

for (let i = 5; i >= 1; i--) {
  console.log(i);
}

Output:

5
4
3
2
1

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🧪 Nested Loops

You can put one loop inside another to create nested loops:

for (let i = 1; i <= 2; i++) {
  for (let j = 1; j <= 2; j++) {
    console.log(`i: ${i}, j: ${j}`);
  }
}

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📘 Summary

• Use for loops to repeat code a set number of times.
• Common for iterating over arrays or counting.
• Be careful with loop conditions to avoid infinite loops.
• Useful for both forward and reverse iterations.

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