Binary Search Iterative Approach in DSA C++ - 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 using a fast search method.

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

📋 What You'll Learn

Create a sorted array of integers representing book IDs

Set up variables to track the search range (start and end indices)

Implement the iterative binary search logic using a while loop

Print the index of the found book ID 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 catalog or a product in an online store.

💼 Career

Understanding binary search is essential for software developers and engineers to write efficient search algorithms and optimize performance in applications.

1

Create the sorted array of book IDs

Create an integer array called bookIDs with these exact values in order: 101, 203, 305, 407, 509, 611, 713

DSA C++

// Create the sorted array bookIDs with the given values
// Your code here

Hint

Use curly braces to list the numbers inside the array.

2

Set up the search range variables

Create two integer variables called start and end. Set start to 0 and end to 6 (the last index of bookIDs)

DSA C++

int bookIDs[] = {101, 203, 305, 407, 509, 611, 713};
// Create start and end variables for the search range
// Your code here

Hint

Remember the first index is 0 and the last index is the array length minus one.

3

Implement the iterative binary search logic

Write a while loop that runs while start is less than or equal to end. Inside the loop, calculate the middle index mid as (start + end) / 2. If bookIDs[mid] equals 509, break the loop. If bookIDs[mid] is less than 509, set start to mid + 1. Otherwise, set end to mid - 1. After the loop, create an integer variable result that is mid if bookIDs[mid] equals 509, else -1

DSA C++

int bookIDs[] = {101, 203, 305, 407, 509, 611, 713};
int start = 0;
int end = 6;
// Implement the iterative binary search for 509
// Your code here

Hint

Use a while loop and update start or end based on comparison with 509.

4

Print the search result

Write a std::cout statement to print the value of result followed by a newline

DSA C++

int bookIDs[] = {101, 203, 305, 407, 509, 611, 713};
int start = 0;
int end = 6;
int mid;
while (start <= end) {
    mid = (start + end) / 2;
    if (bookIDs[mid] == 509) {
        break;
    } else if (bookIDs[mid] < 509) {
        start = mid + 1;
    } else {
        end = mid - 1;
    }
}
int result = (bookIDs[mid] == 509) ? mid : -1;
// Print the result
// Your code here

Hint

Use std::cout << result << std::endl; to print the index.