Merge pull request #930 from kvedala/fixes/929_pull

[fixes] issues from #929

sorting/insertion_sort.cpp

@@ -4,22 +4,18 @@
  * \brief [Insertion Sort Algorithm
  * (Insertion Sort)](https://en.wikipedia.org/wiki/Insertion_sort)
  *
- * \author
- *
  * \details
  * Insertion sort is a simple sorting algorithm that builds the final
  * sorted array one at a time. It is much less efficient compared to
  * other sorting algorithms like heap sort, merge sort or quick sort.
  * However it has several advantages such as
- * <pre>
- * 1 - easy to implement
- * 2 - For small set of data it is quite efficient
- * 3 - More efficient that other Quadratic complexity algorithms like
+ * 1. Easy to implement
+ * 2. For small set of data it is quite efficient
+ * 3. More efficient that other Quadratic complexity algorithms like
  *    Selection sort or bubble sort.
- * 4 - It's stable that is it does not change the relative order of
+ * 4. It's stable that is it does not change the relative order of
  *    elements with equal keys
- * 5 - Works on hand means it can sort the array or list as it receives.
- * </pre>
+ * 5. Works on hand means it can sort the array or list as it receives.
  *
  * It is based on the same idea that people use to sort the playing cards in
  * their hands.
@@ -27,44 +23,42 @@
  * of elements as soon as we find a unsorted element that is a misplaced
  * element we place it at a sorted position.
  *
- * Suppose initially we have
- * <pre>
- * 4 3 2 5 1
- *
- * we start traversing from 4 till we reach 1
+ * Example execution steps:
+ * 1. Suppose initially we have
+ * \f{bmatrix}{4 &3 &2 &5 &1\f}
+ * 2. We start traversing from 4 till we reach 1
  * when we reach at 3 we find that it is misplaced so we take 3 and place
  * it at a correct position thus the array will become
- *
- * 3 4 2 5 1
- *
- * in the next iteration we are at 2 we find that this is also misplaced so
+ * \f{bmatrix}{3 &4 &2 &5 &1\f}
+ * 3. In the next iteration we are at 2 we find that this is also misplaced so
  * we place it at the correct sorted position thus the array in this iteration
  * becomes
- *
- * 2 3 4 5 1
- *
- * we does not do anything with 5 and move on to the next iteration and select
- * 1 which is misplaced and place it at correct position. Thus, we have
- *
- * 1 2 3 4 5
- * </pre>
- *
+ * \f{bmatrix}{2 &3 &4 &5 &1\f}
+ * 4. We do not do anything with 5 and move on to the next iteration and
+ * select 1 which is misplaced and place it at correct position. Thus, we have
+ * \f{bmatrix}{1 &2 &3 &4 &5\f}
  */
 
 #include <algorithm>
 #include <cassert>
 #include <iostream>
+#include <vector>
 
+/** \namespace sorting
+ * \brief Sorting algorithms
+ */
+namespace sorting {
 /** \brief
  * Insertion Sort Function
  *
- * @param arr Array to be sorted
+ * @tparam T type of array
+ * @param [in,out] arr Array to be sorted
  * @param n Size of Array
- *
  */
-void insertionSort(int *arr, int n) {
+template <typename T>
+void insertionSort(T *arr, int n) {
     for (int i = 1; i < n; i++) {
-        int temp = arr[i];
+        T temp = arr[i];
         int j = i - 1;
         while (j >= 0 && temp < arr[j]) {
             arr[j + 1] = arr[j];
@@ -74,17 +68,82 @@ void insertionSort(int *arr, int n) {
     }
 }
 
+/** Insertion Sort Function
+ *
+ * @tparam T type of array
+ * @param [in,out] arr pointer to array to be sorted
+ */
+template <typename T>
+void insertionSort(std::vector<T> *arr) {
+    size_t n = arr->size();
+
+    for (size_t i = 1; i < n; i++) {
+        T temp = arr[0][i];
+        int32_t j = i - 1;
+        while (j >= 0 && temp < arr[0][j]) {
+            arr[0][j + 1] = arr[0][j];
+            j--;
+        }
+        arr[0][j + 1] = temp;
+    }
+}
+
+}  // namespace sorting
+
+/**
+ * @brief Create a random array objecthelper function to create a random array
+ *
+ * @tparam T type of array
+ * @param arr array to fill (must be pre-allocated)
+ * @param N number of array elements
+ */
+template <typename T>
+static void create_random_array(T *arr, int N) {
+    while (N--) {
+        double r = (std::rand() % 10000 - 5000) / 100.f;
+        arr[N] = static_cast<T>(r);
+    }
+}
+
 /** Test Cases to test algorithm */
 void tests() {
     int arr1[10] = {78, 34, 35, 6, 34, 56, 3, 56, 2, 4};
-    insertionSort(arr1, 10);
+    std::cout << "Test 1... ";
+    sorting::insertionSort(arr1, 10);
     assert(std::is_sorted(arr1, arr1 + 10));
-    std::cout << "Test 1 Passed" << std::endl;
+    std::cout << "passed" << std::endl;
 
     int arr2[5] = {5, -3, 7, -2, 1};
-    insertionSort(arr2, 5);
+    std::cout << "Test 2... ";
+    sorting::insertionSort(arr2, 5);
     assert(std::is_sorted(arr2, arr2 + 5));
-    std::cout << "Test 2 Passed" << std::endl;
+    std::cout << "passed" << std::endl;
+
+    float arr3[5] = {5.6, -3.1, -3.0, -2.1, 1.8};
+    std::cout << "Test 3... ";
+    sorting::insertionSort(arr3, 5);
+    assert(std::is_sorted(arr3, arr3 + 5));
+    std::cout << "passed" << std::endl;
+
+    std::vector<float> arr4({5.6, -3.1, -3.0, -2.1, 1.8});
+    std::cout << "Test 4... ";
+    sorting::insertionSort(&arr4);
+    assert(std::is_sorted(std::begin(arr4), std::end(arr4)));
+    std::cout << "passed" << std::endl;
+
+    int arr5[50];
+    std::cout << "Test 5... ";
+    create_random_array(arr5, 50);
+    sorting::insertionSort(arr5, 50);
+    assert(std::is_sorted(arr5, arr5 + 50));
+    std::cout << "passed" << std::endl;
+
+    float arr6[50];
+    std::cout << "Test 6... ";
+    create_random_array(arr6, 50);
+    sorting::insertionSort(arr6, 50);
+    assert(std::is_sorted(arr6, arr6 + 50));
+    std::cout << "passed" << std::endl;
 }
 
 /** Main Function */
@@ -93,9 +152,13 @@ int main() {
     tests();
 
     /// For user insteraction
-    int n;
-    std::cout << "Enter the length of your array : ";
+    size_t n;
+    std::cout << "Enter the length of your array (0 to exit): ";
     std::cin >> n;
+    if (n == 0) {
+        return 0;
+    }
+
     int *arr = new int[n];
     std::cout << "Enter any " << n << " Numbers for Unsorted Array : ";
 
@@ -103,7 +166,7 @@ int main() {
         std::cin >> arr[i];
     }
 
-    insertionSort(arr, n);
+    sorting::insertionSort(arr, n);
 
     std::cout << "\nSorted Array : ";
     for (int i = 0; i < n; i++) {