Bubble Sort in C++

Sorting operations are at the core of computer science, and one of the first sorting algorithms that newcomers encounter is Bubble Sort. While it is not the most efficient sorting method, but Bubble Sort serves as an excellent starting point for novices, facilitating a grasp of sorting principles and providing an entry into the world of algorithms. In this comprehensive blog post, we will embark on a detailed journey through Bubble Sort, encompassing its algorithm, operational methodology, C++ implementation, analysis of time complexity, and exploration of alternative sorting techniques. By the end of this article, readers will have gained a profound understanding of Bubble Sort's significance in the realm of sorting algorithms.

Bubble Sort Algorithm

Bubble Sort represents a straightforward comparison-based sorting algorithm, which systematically traverses a list, conducts comparisons between adjacent elements, and arranges them accordingly if they are out of order. This iterative process persists until the entire list is in ascending order. The fundamental steps of the algorithm can be succinctly summarized as follows:

Commence by comparing the first element with the second, the second with the third, and so forth.
Execute a swap operation if an element is greater than its immediate successor.
Continue this pairwise comparison process until the largest element 'bubbles up' to the end of the array.
Recursively repeat the same steps for the remaining unsorted elements, excluding those already correctly positioned.
Iterate through these passes until no more swaps are required, signifying the completion of the sorting process.

The simplicity of Bubble Sort makes it an excellent choice for educational purposes, facilitating a clear grasp of basic sorting concepts.

How Bubble Sort Functions:

Illustrating the mechanics of Bubble Sort is best achieved through a practical example. Consider an unsorted array, such as [10, 5, 15, 0, 12]. In the initial pass, Bubble Sort compares adjacent elements and performs swaps where it is necessary. After the first pass, the largest element (15) 'bubbles up' to the end of the array:

[5, 10, 0, 12, 15]

In the subsequent pass, the second-largest element (12) migrates to the second-last position:

[5, 0, 10, 12, 15]

This process iterates until the entire array is sorted, effectively relocating the largest unsorted element to its correct position in each pass.

Bubble Sort's Inefficiency

While Bubble Sort is renowned for its simplicity in comprehension and implementation, its efficiency reduces significantly when applied to sizable datasets. The primary culprit behind its inefficiency lies in its time complexity, which is O(n^2) for both average and worst-case scenarios. This quadratic growth implies that as the array size increases, the time required for sorting undergoes exponential expansion. Additionally, Bubble Sort necessitates a multitude of swaps between neighboring elements, incurring substantial memory access costs. Consequently, for real-world applications that demand efficiency, alternative sorting algorithms such as Quick Sort and Merge Sort are favored choices.

Implementing Bubble Sort in C++

If we want to translate Bubble Sort into C++, a series of nested loops is employed to facilitate comparisons and swaps between adjacent elements. Below is a comprehensive C++ program for Bubble Sort:

#include <iostream>
 
void bubbleSort(int arr[], int n) {
    int i, j;
    bool flag;
    for(i = 0; i < n; i++) {
        flag = false;
        for(j = 0; j < n-i-1; j++) {
            if(arr[j] > arr[j+1]) {
                std::swap(arr[j], arr[j+1]);
                flag = true;
            }
        }
        if(!flag) {
            break;
        }
    }
}
 
int main() {
    int arr[] = {10, 5, 15, 0, 12};
    int n = sizeof(arr) / sizeof(arr[0]);
    
    std::cout << "Unsorted Array: ";
    for(int i = 0; i < n; i++)
        std::cout << arr[i] << " ";
    std::cout << std::endl;
    
    bubbleSort(arr, n);
    
    std::cout << "Sorted Array: ";
    for(int i = 0; i < n; i++)
        std::cout << arr[i] << " ";
    
    return 0;
}

Output

Unsorted Array: 10 5 15 0 12 
Sorted Array: 0 5 10 12 15

Conclusion:

In conclusion, Bubble Sort serves as an introductory sorting algorithm, providing beginners with valuable insights into sorting principles and the foundations of algorithmic thinking. While its simplicity renders it accessible, Bubble Sort's inefficiency in terms of time complexity and memory usage limits its practicality for sorting substantial datasets. Nonetheless, mastering Bubble Sort represents a significant milestone in a programmer's journey, as it establishes a solid groundwork for comprehending more intricate sorting algorithms and fundamental computer science concepts. As one delves deeper into the universe of algorithms, a multitude of sorting methods with distinct strengths and applications will unfold, expanding one's horizons.

Next TopicDDA line drawing algorithm in C++

← prev next →