Determinant of a nxn Matrix c++ program

#include<iostream>
#include<math.h>
#include<conio.h>
using namespace std;
double d=0;
double det(int n,double mat[10][10]);   // u can replace 10 with any number


int main()
{int n;
cout<<"enter the order of matrix" ;
cin>>n;
double mat[10][10];
int i,j;
cout<<"enter the elements"<<endl;
for(i=0;i<n;i++)
for(j=0;j<n;j++)
cin>>mat[i][j];
cout<<"\ndeterminant    "<<det(n,mat);
getch();
}


double det(int n,double mat[10][10])
  double submat[10][10]; 
if(n==2) return( (mat[0][0]*mat[1][1])-(mat[1][0]*mat[0][1]));
else
{  for(c=0;c<n;c++)
   {  subi=0;   //submatrix's i value
      for(i=1;i<n;i++)
          {  subj=0;
             for(j=0;j<n;j++)
                    {if(j==c)
                      continue;
                     submat[subi][subj]=mat[i][j];
                     subj++;
                     }
              subi++;
   
            }
      d=d+(pow(-1,c)*mat[0][c]*det(n-1 ,submat));
    }
}
return d;
}