Algorithm for the Iterative Quicksort
After understanding the quicksort, we will see how we can implement quicksort using loops:
1. Initialize stack with size = end - start + 1. 2. Push first and last in the stack. 3. Now, till the stack is empty, do a. Set last = stack[top] and pop stack. b. Set first = stack[top] and pop stack. c. Call pivot_pos = partition(arr, first, end) d. If pivot_pos - 1 > first. i. push first to stack. ii. push pivot_pos - 1 to stack. e. If pivot_pos + 1 < last. i. push pivot_pos + 1 to stack. ii. push last.
C++ Program For Iterative Quick Sort
Quicksort also known as partition-exchange sort is a divide-and-conquer sorting algorithm that works by selecting a pivot element from the array and partitioning the other elements into two sub-arrays, according to whether they are less than or greater than the pivot element. The sub-arrays can then be sorted in the same way and this continues till the sub-arrays only consist of a single element.
In C++, quicksort can be implemented using both recursively and iteratively. In this article, we will learn how to implement quicksort in C++ iteratively.