C quicksort (#44)

* Add C example for recursion

* Add loop_sum in c

* Add recursive_sum in c

* Add quicksort in c

04_quicksort/c/01_loop_sum.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+
+int sum(int *arr, int size) {
+	int total = 0;
+	for (int i = 0; i < size; i++) {
+		total += arr[i];
+	}
+	return total;
+}
+
+int main(void) {
+	int arr[4] = { 1,2,3,4 };
+	printf("%d", sum(arr, 4));
+
+	return 0;
+}

04_quicksort/c/02_recursive_sum.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int sum(int *arr, int index, int size) {
+	if (index == size)
+		return 0;
+	return arr[index] + sum(arr, index + 1, 4);
+}
+
+int main(void) {
+	int arr[4] = { 1,2,3,4 };
+	printf("%d", sum(arr, 0, 4));
+
+	return 0;
+}

04_quicksort/c/05_quicksort.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+
+// Quick Sort
+void quick_sort(int *array, int start, int end) {
+	if (start < end) {
+		int q = partition(array, start, end);
+		quick_sort(array, start, q - 1);
+		quick_sort(array, q + 1, end);
+	}
+}
+// Partition by pivot
+int partition(int *array, int start, int end) {
+	int pivot = array[end];
+	int i = start - 1;
+	int temp = 0;
+	for (int j = start; j < end; j++) {
+		if (array[j] <= pivot) {
+			i++;
+			temp = array[i];
+			array[i] = array[j];
+			array[j] = temp;
+		}
+	}
+	temp = array[i + 1];
+	array[i + 1] = array[end];
+	array[end] = temp;
+
+	return i + 1;
+}
+
+int main(void) {
+	int arr[4] = {10, 5, 2, 3};
+	quick_sort(arr, 0, 3);
+	// Print result
+	for (int i = 0; i < 4; i++) {
+		printf("%d ", arr[i]);
+	}
+
+	return 0;
+}