Binary Search Iterative Approach in DSA Javascript - Build from Scratch

Binary Search Iterative Approach

📖 Scenario: You have a sorted list of book IDs in a library system. You want to quickly find if a specific book ID exists in the list using a fast search method.

🎯 Goal: Build a program that uses the iterative binary search method to find a target book ID in a sorted array of book IDs.

📋 What You'll Learn

Create a sorted array called bookIDs with the exact values: [101, 203, 305, 407, 509, 611, 713]

Create a variable called targetID and set it to 407

Write an iterative binary search function called binarySearch that takes arr and target as parameters

Use a while loop with variables left and right to search for targetID in bookIDs

Print the index of targetID if found, or -1 if not found

💡 Why This Matters

🌍 Real World

Binary search is used in many software systems to quickly find data in sorted lists, such as searching for a book in a library database or a contact in a phone book.

💼 Career

Understanding binary search is important for software developers and engineers because it teaches efficient searching techniques and algorithmic thinking, which are often tested in technical interviews.

1

Create the sorted array of book IDs

Create a sorted array called bookIDs with these exact values: [101, 203, 305, 407, 509, 611, 713]

DSA Javascript

// Create the sorted array bookIDs
// Your code here

Hint

Use const to declare the array and include all numbers in order.

2

Set the target book ID to search

Create a variable called targetID and set it to 407

DSA Javascript

const bookIDs = [101, 203, 305, 407, 509, 611, 713];
// Create the targetID variable
// Your code here

Hint

Use const to declare targetID and assign the number 407.

3

Write the iterative binary search function

Write a function called binarySearch that takes parameters arr and target. Inside it, create variables left set to 0 and right set to arr.length - 1. Use a while loop with the condition left <= right. Inside the loop, calculate mid as the floor of (left + right) / 2. If arr[mid] equals target, return mid. If arr[mid] is less than target, set left to mid + 1. Otherwise, set right to mid - 1. After the loop, return -1.

DSA Javascript

const bookIDs = [101, 203, 305, 407, 509, 611, 713];
const targetID = 407;

// Write the binarySearch function below
// Your code here

Hint

Follow the binary search steps carefully inside the while loop.

4

Print the search result

Call the binarySearch function with bookIDs and targetID as arguments. Print the returned index using console.log.

DSA Javascript

const bookIDs = [101, 203, 305, 407, 509, 611, 713];
const targetID = 407;

function binarySearch(arr, target) {
    let left = 0;
    let right = arr.length - 1;
    while (left <= right) {
        let mid = Math.floor((left + right) / 2);
        if (arr[mid] === target) {
            return mid;
        } else if (arr[mid] < target) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
    return -1;
}

// Print the index of targetID in bookIDs
// Your code here

Hint

Use console.log(binarySearch(bookIDs, targetID)) to print the result.