#include <iostream>
#include <cmath>
using namespace std;

float Determinant(float **a,int n)
{
   int i, j, j1, j2;
   float det = 0;
   float **m = NULL;

   if (n < 1) {
       return -1;
   } else if (n == 1) {
      det = a[0][0];
   } else if (n == 2) {
      det = a[0][0] * a[1][1] - a[1][0] * a[0][1];
   } else { // n > 2
      det = 0;
      for (j1 = 0; j1 < n; j1++) {
         m = new float* [n];
         for (i = 0; i < n-1; i++)
            m[i] = new float [n];
         for (i = 1; i < n; i++) {
            j2 = 0;
            for (j = 0; j < n; j++) {
               if (j == j1)
                  continue;
               m[i-1][j2] = a[i][j];
               j2++;
            }
         }
         det += pow(-1.0,1.0+j1+1.0)*a[0][j1]*Determinant(m, n-1);
         for (i = 0; i < n - 1; i++)
            free(m[i]);
         free(m);
      }
   }
   return(det);
}