find min in c++

findmin.cpp

#include <iostream>
#include <ctime>
#include <cstdlib>
#include <random>

#define N 1000000
#define H 256
#define TRIALS 60

float matrix [N][H];
int mins[N];
float min;
int minidx;

int main() {

  std::clock_t start;
  start = std::clock();

  srand (static_cast <unsigned> (time(0)));

  for (int i=0; i<N; i++) {
    for (int j=0; j<H; j++) {
      matrix[i][j] = static_cast <float> (rand()) / static_cast <float> (RAND_MAX);
    }
  }

  std::cout << "Time: " << (std::clock() - start) / (double)(CLOCKS_PER_SEC / 1000) << " ms creating array" << std::endl;

  start = std::clock();

  for (int k=0; k<TRIALS; k++ ) {
    for (int i=0; i<N; i++) {
      minidx = 0;
      min = matrix[i][0];
      for (int j=1; j<H; j++) {
        if (matrix[i][j] < min) {
          min    = matrix[i][j];
          minidx = j;
        }
      }
      mins[i] = minidx;
    }
  }

  std::cout << "Time: " <<  (double)(((std::clock()-start)) / 1000) << " ms finding mins" << std::endl;

}