qsort: add another way to read numbers and test

impls/qsort.cpp

@@ -6,6 +6,9 @@
  */
 #include <cstdio>
 #include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <vector>
 
 #define ARR_SIZE(XS) (sizeof(XS) / sizeof((XS)[0]))
 #define SWAP(A, B) \
@@ -50,25 +53,37 @@ void quicksort(int *arr, int arr_size)
   }
 }
 
-int main(void)
+int main(int argc, char *argv[])
 {
-  // randomly generate some numbers
+  (void)argc;
+  (void)argv;
 
-  int *arr = new int[TEST_SIZE];
+#define TEST_SIZE 10
+  // randomly generate some numbers
+  int *arr     = new int[TEST_SIZE];
+  int arr_size = TEST_SIZE;
 
   for (size_t i = 0; i < TEST_SIZE; ++i)
-  {
     arr[i] = rand() % (2L << 30);
-  }
+
+  // Use nums.txt
+  // std::ifstream input(argc > 1 ? argv[1] : "nums.txt");
+  // std::vector<int> num_vec;
+
+  // for (std::string line; std::getline(input, line);
+  //      num_vec.push_back(std::stoi(line)))
+  //   continue;
+  // int *arr = &num_vec[0];
+  // int arr_size = num_vec.size();
 
   printf("Before: ");
-  print_arr(arr, TEST_SIZE);
+  print_arr(arr, arr_size);
   printf("\n");
 
-  quicksort(arr, TEST_SIZE);
+  quicksort(arr, arr_size);
 
   printf("After: ");
-  print_arr(arr, TEST_SIZE);
+  print_arr(arr, arr_size);
   printf("\n");
 
   delete[] arr;