// builtinsort.cpp

#include <algorithm> 
#include <assert.h>
#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>

static int random(int ceiling) {
  return static_cast<int>((static_cast<float>(rand()) / RAND_MAX) * ceiling);
}

static void scramble(int a[], int aSize) {
  for (int i = 0; i < aSize; i++)
    std::swap(a[i], a[random(aSize)]);
}

static void makeScrambledArray(int a[], int size) {
  for (int i = 0; i < size; i++)
    a[i] = i;
  scramble (a, size);
}

// BEGIN-ALGORITHM
static void builtinsort(int a[], int aSize)
{
  sort (a, a + aSize);
}
// END-ALGORITHM

int main() {
  const int trials = 1000;
  double totalTime = 0;
  for (int i = 0; i < trials; i++) 
    {
      const int aSize = 10000;
      int a [aSize];
      makeScrambledArray(a, aSize);
      clock_t startTime = clock();
      builtinsort(a, aSize);
      clock_t endTime = clock();
      double seconds = 
        static_cast<double>(endTime - startTime) / CLOCKS_PER_SEC;
      totalTime += seconds;
    }
  cout << totalTime / trials << endl;
}