Below is the program in C++ to find the determinant of matrix

#include<iostream.h>
#include<conio.h>
#include<math.h>
#include<stdlib.h>

typedef struct
{
       int order;
       int **ar;        //for a 2-d array

}matrix;

int create( matrix *a,int order)
{
      if(order<1)
        return 0;             //checks for invalid order

      a->order=order;

      a->ar= (int**) malloc(order*sizeof(int *)); //allocate space for each row

      if(!a->ar)
        return 0;            //checks if memory is allocated

     for(int i=0;i<order;i++)
      { a->ar[i]=(int*) malloc(order*sizeof(int));
        if(!a->ar)
         return 0;
      }
       return 1;
}

void input(matrix *a )
{
        int i,j;
        for( i = 0; i < a->order; i++ )
         for( j = 0; j < a->order; j++ )
            {
                printf("Enter element at ( %d, %d ): ", i+1, j+1 );
                scanf("%d", &a->ar[i][j] );
             }
}

void display( matrix *a )
{
            int i,j;
           
            if( a->order < 1 )
            return;
           
            for( i = 0; i < a->order; i++ )
                {
                for( j = 0; j < a->order; j++ )
                printf("%5d ", a->ar[i][j] );
               
                printf("\n");
                }
}
int calcminor(matrix *a, matrix *minor, int row,int column)

{
       int p,q;

       if(a->order<=1||row>=a->order||column>=a->order)
     return 0;

       if(!create(minor,a->order-1))
     return 0;

       p=q=0;

       for(int i=0;i<a->order;i++)
         if(i!=row)
     {
           q=0;
         for(int j=0;j<a->order;j++)
           { if(j!=column)
           minor->ar[p][q]=a->ar[i][j];
           q++;
           }
        p++;
     }
     return 1;
}

void destroy(matrix *a)

{
     if(a->order<1)
       return;

       for(int i=0;i<a->order;i++)
         free(a->ar[i]);         // free space for the column

         free(a->ar);       //free memory  for rows
         a->order=0;
}

int calcdet(matrix *a)

{
       int result=0;

       matrix minor;

       if(a->order<1)
         return 0;

       if(a->order==1)      // stopping condition
         return a->ar[0][0];     //returns 0,0 element

       for(int i=0;i<a->order;i++)

     {
          if(!calcminor(a,&minor,0,i))
             return 0;
          result+=( pow(-1,i)*a->ar[0][i]*calcdet(&minor));

          destroy(&minor);
     }

       return result;
}


int main()

{
    matrix a;
    int order;
    cout<<"\nEnter The Order of The Square Matrix :";
    cin>>order;

    if(!create(&a,order))
       {
           cout<<"\n The Matrix Could Not Be Created !!!! ";
           getch();
          return 0;
       }
       input(&a);
       cout<<"The Matrix Is :\n";
       display(&a); 


    cout<<"\n The Determinant Of The Matrix Is : "<<calcdet(&a);

    getch();
    return 0;
}