qsort: generate random numbers in hand instead of reading them

Makefile

@@ -15,6 +15,9 @@ list.out: impls/list.cpp
 bsearch.out: impls/bsearch.cpp
 	$(CC) $(CFLAGS) $^ -o $@
 
+qsort.out: impls/qsort.cpp
+	$(CC) $(CFLAGS) $^ -o $@
+
 vec.out: impls/vec.c
 	$(CC) $(CFLAGS) $^ -o $@
 

impls/qsort.cpp

@@ -16,14 +16,14 @@
     (A) ^= (B);    \
   } while (0)
 
-#define TEST_SIZE 20
+#define TEST_SIZE 10
 
 void print_arr(int *arr, int size)
 {
-  printf("{");
-  for (int i = 0; i < size - 1; ++i)
-    printf("%d, ", arr[i]);
-  printf("%d}", arr[size - 1]);
+  printf("{\n");
+  for (int i = 0; i < size; ++i)
+    printf("  %d,\n", arr[i]);
+  printf("}\n");
 }
 
 void quicksort(int *arr, int arr_size)
@@ -70,29 +70,26 @@ void quicksort(int *arr, int arr_size)
 
 int main(void)
 {
-  int arr[TEST_SIZE] = {0};
-  const int size     = TEST_SIZE;
+  // randomly generate some numbers
 
-  // Generate a completely reverse ordered list
-  /*for (size_t i = 0; i < size; ++i) */
-  /*  arr[TEST_SIZE - i - 1] = i;*/
+  int *arr = new int[TEST_SIZE];
 
-  // Generate a list where the first half is completely sorted and the
-  // other half is in reverse order.
-  for (size_t i = 0; i < size / 2; ++i)
-    arr[i] = i;
-  for (size_t i = size / 2; i < size; ++i)
-    arr[TEST_SIZE - (i - size / 2) - 1] = i;
+  for (size_t i = 0; i < TEST_SIZE; ++i)
+  {
+    arr[i] = rand() % (2L << 30);
+  }
 
   printf("Before: ");
-  print_arr(arr, size);
+  print_arr(arr, TEST_SIZE);
   printf("\n");
 
-  quicksort(arr, size);
+  quicksort(arr, TEST_SIZE);
 
   printf("After: ");
-  print_arr(arr, size);
+  print_arr(arr, TEST_SIZE);
   printf("\n");
 
+  delete[] arr;
+
   return 0;
 }