quick_sort.c: Add Quick Sort in C

This adds Quick Sort algorithm written in C

Closes #146

Author: 123vivekr

README.md

@@ -13,8 +13,8 @@ This repository contains examples of various algorithms written on different pro
 | Algorithm                                                                                       | C                                     | CPP                                   | Java                                  | Python                                |
 |:----------------------------------------------------------------------------------------------- |:-------------------------------------:|:-------------------------------------:|:-------------------------------------:|:-------------------------------------:|
 | [Euclidean GCD](https://en.wikipedia.org/wiki/Euclidean_algorithm)                              | [:octocat:](euclidean_gcd/C)          |                                      | [:octocat:](euclidean_gcd/Java)        | [:octocat:](euclidean_gcd/Python)     |
-| [QuickSort](https://en.wikipedia.org/wiki/Quicksort)                                            |                                       |                                       |                                       | [:octocat:](quicksort/Python)         |
 | [Merge Sort](https://en.wikipedia.org/wiki/Merge_sort)                                          | [:octocat:](merge_sort/C)             |                                       |                                       | [:octocat:](merge_sort/Python)        |
+| [QuickSort](https://en.wikipedia.org/wiki/Quicksort)                                            | [:octocat:](quicksort/C)                                      |                                       |                                       | [:octocat:](quicksort/Python)         |
 | [Insertion Sort](https://en.wikipedia.org/wiki/Insertion_sort)                                  | [:octocat:](insertion_sort/C)         | [:octocat:](insertion_sort/Cpp)       |                                       | [:octocat:](insertion_sort/Python)    |
 | [Counting Sort](https://en.wikipedia.org/wiki/Counting_sort)                                    |[:octocat:](counting_sort/C)           | [:octocat:](counting_sort/Cpp)                                       |                                       | [:octocat:](counting_sort/Python)     |
 | [Radix Sort](https://en.wikipedia.org/wiki/Radix_sort)                                          |                                       | [:octocat:](radix_sort/Cpp)                                       |                                       | [:octocat:](radix_sort/Python)        |

quicksort/C/quick_sort.c

@@ -0,0 +1,53 @@
+#include <stdio.h>
+
+void quick_sort(int[], int, int);
+void print_array(int[], int);
+int partition(int[], int, int);
+void swap(int*, int*);
+
+int main() {
+	int arr[] = {45, 92, 54, 23, 6, 4, 12};
+	int n = sizeof(arr) / sizeof(arr[0]);
+	quick_sort(arr, 0, n);
+	printf("Sorted array: \n");
+	print_array(arr, n);
+}
+
+void swap(int *a, int *b) {
+	int temp = *a;
+	*a = *b;
+	*b = temp;
+}
+
+/* Quick Sort algorithm */
+void quick_sort(int arr[], int lb, int ub) {
+	if (lb < ub) {
+		int pi = partition(arr, lb, ub);
+
+		quick_sort(arr, lb, pi - 1);
+		quick_sort(arr, pi + 1, ub);
+	}
+}
+
+/* Partitioning function */
+int partition(int arr[], int low, int high) {
+	int i = low + 1;
+	int piv = arr[low];
+
+	for (int j = low + 1; j <= high; ++j) {
+		if (arr[j] < piv) {
+			swap(&arr[i], &arr[j]);
+			i++;
+		}
+	}
+	swap(&arr[low], &arr[i - 1]);
+	return i - 1;
+}
+
+/* Function to print array */
+void print_array(int arr[], int size) {
+	int i;
+	for (i = 0; i < size; i++)
+		printf("%d ", arr[i]);
+	printf("\n");
+}