insertion_sort_recursive (#647)

* insertion_sort_recursive

* feat: add insertion sort recursive algorithm

* Update sorting/insertion_sort_recursive.c

Co-authored-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* Update sorting/insertion_sort_recursive.c

Co-authored-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* Update insertion_sort_recursive.c

* Update sorting/insertion_sort_recursive.c

Co-authored-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* Update sorting/insertion_sort_recursive.c

Co-authored-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* Update sorting/insertion_sort_recursive.c

Co-authored-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

Co-authored-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

sorting/insertion_sort_recursive.c

@@ -0,0 +1,71 @@
+/**
+ * @file
+ * @brief [Insertion sort](https://en.wikipedia.org/wiki/Insertion_sort)
+ * algorithm implementation.
+ */
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+/**
+ * @addtogroup sorting Sorting algorithms
+ * @{
+ */
+/**
+ * Insertion sort algorithm implements using Recursion 
+ * @param arr array to be sorted
+ * @param size size of array
+ */
+void RecursionInsertionSort(int *arr, int size)
+{
+    if(size <= 0)
+    {
+        return;
+    }
+    
+    // marking recursive call to reach starting element
+    RecursionInsertionSort(arr,size-1);
+    
+    int key = arr[size-1];
+    int j = size-2;
+    // swapping logic for insertion sort
+    while(j >= 0 && arr[j] > key)
+    {
+        arr[j+1] = arr[j];
+        j--;
+    }
+    arr[j+1] = key;
+}
+/** @} */
+/** Test function
+  * @returns None
+  */
+static void test()
+{
+    const int size = rand() % 500; /* random array size */
+    int *arr = (int *)calloc(size, sizeof(int));
+
+    /* generate size random numbers from -50 to 49 */  
+    for (int i = 0; i < size; i++)
+    {
+        arr[i] = (rand() % 100) - 50;/* signed random numbers */
+    }
+    RecursionInsertionSort(arr, size);
+    for (int i = 0; i < size  ; ++i)
+    {
+        assert(arr[i] <= arr[i + 1]);
+    }
+    free(arr);
+}
+
+/** Main function
+ *  @returns integer 0
+ */
+int main(int argc, const char *argv[])
+{
+    /* Intializes random number generator */
+    srand(time(NULL));
+    test();
+    return 0;
+}