fix dynamic array issues in sorting folder

sorting/merge_sort.cpp

@@ -1,57 +1,47 @@
 #include <iostream>
-using namespace std;
 
-void merge(int arr[], int l, int m, int r)
-{
+void merge(int arr[], int l, int m, int r) {
     int i, j, k;
     int n1 = m - l + 1;
     int n2 = r - m;
 
-    int L[n1], R[n2];
+    int *L = new int[n1], *R = new int[n2];
 
-    for (i = 0; i < n1; i++)
-        L[i] = arr[l + i];
-    for (j = 0; j < n2; j++)
-        R[j] = arr[m + 1 + j];
+    for (i = 0; i < n1; i++) L[i] = arr[l + i];
+    for (j = 0; j < n2; j++) R[j] = arr[m + 1 + j];
 
     i = 0;
     j = 0;
     k = l;
-    while (i < n1 && j < n2)
-    {
-        if (L[i] <= R[j])
-        {
+    while (i < n1 && j < n2) {
+        if (L[i] <= R[j]) {
             arr[k] = L[i];
             i++;
-        }
-        else
-        {
+        } else {
             arr[k] = R[j];
             j++;
         }
         k++;
     }
 
-    while (i < n1)
-    {
+    while (i < n1) {
         arr[k] = L[i];
         i++;
         k++;
     }
 
-    while (j < n2)
-    {
+    while (j < n2) {
         arr[k] = R[j];
         j++;
         k++;
     }
+
+    delete[] L;
+    delete[] R;
 }
 
-void mergeSort(int arr[], int l, int r)
-{
-    if (l < r)
-    {
-
+void mergeSort(int arr[], int l, int r) {
+    if (l < r) {
         int m = l + (r - l) / 2;
 
         mergeSort(arr, l, m);
@@ -61,33 +51,31 @@ void mergeSort(int arr[], int l, int r)
     }
 }
 
-void show(int A[], int size)
-{
+void show(int A[], int size) {
     int i;
-    for (i = 0; i < size; i++)
-        cout << A[i] << "\n";
+    for (i = 0; i < size; i++) std::cout << A[i] << "\n";
 }
 
-int main()
-{
+int main() {
     int size;
-    cout << "\nEnter the number of elements : ";
+    std::cout << "\nEnter the number of elements : ";
 
-    cin >> size;
+    std::cin >> size;
 
-    int arr[size];
+    int *arr = new int[size];
 
-    cout << "\nEnter the unsorted elements : ";
+    std::cout << "\nEnter the unsorted elements : ";
 
-    for (int i = 0; i < size; ++i)
-    {
-        cout << "\n";
-        cin >> arr[i];
+    for (int i = 0; i < size; ++i) {
+        std::cout << "\n";
+        std::cin >> arr[i];
     }
 
     mergeSort(arr, 0, size);
 
-    cout << "Sorted array\n";
+    std::cout << "Sorted array\n";
     show(arr, size);
+
+    delete[] arr;
     return 0;
 }