```/* nag_det_real_sym (f03bfc) Example Program.
*
* Copyright 2019 Numerical Algorithms Group.
*
* Mark 27.0, 2019.
*/
#include <math.h>
#include <nag.h>

int main(void)
{
/* Scalars */
Integer exit_status = 0;
Integer i, id, j, n, pda;
double d;
/* Arrays */
char nag_enum_arg[40];
double *a = 0;
/* NAG types */
NagError fail;
Nag_UploType uplo;
Nag_OrderType order;
Nag_MatrixType matrix;
Nag_DiagType diag = Nag_NonUnitDiag;

printf("nag_det_real_sym (f03bfc) Example Program Results\n\n");

/* Skip heading in data file  */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n]", &n);
pda = n;

if (!(a = NAG_ALLOC(n * n, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Define matrix element A_ij in terms of elements of array a[k] */
#ifdef NAG_COLUMN_MAJOR
order = Nag_ColMajor;
#define A(I, J) a[(J-1)*pda+(I-1)]
#else
order = Nag_RowMajor;
#define A(J, I) a[(J-1)*pda+(I-1)]
#endif
for (i = 1; i <= n; i++)
for (j = 1; j <= n; j++)
scanf("%lf", &A(i, j));
scanf("%*[^\n] ");
scanf("%39s %*[^\n] ", nag_enum_arg);
uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);
if (uplo == Nag_Lower) {
matrix = Nag_LowerMatrix;
}
else {
matrix = Nag_UpperMatrix;
}

INIT_FAIL(fail);

/* nag_lapacklin_dpotrf (f07fdc)
* Cholesky factorization of real symmetric positive definite matrix
*/
nag_lapacklin_dpotrf(order, uplo, n, a, pda, &fail);
if (fail.code != NE_NOERROR) {
printf("%s\n", fail.message);
exit_status = 1;
goto END;
}

/* nag_file_print_matrix_real_gen (x04cac)
* Print real general matrix (easy-to-use)
*/
fflush(stdout);
nag_file_print_matrix_real_gen(order, matrix, diag, n, n, a, pda,
"Array A after factorization", NULL, &fail);
if (fail.code != NE_NOERROR) {
printf("%s\n", fail.message);
exit_status = 2;
goto END;
}

/* nag_det_real_sym (f03bfc)
* determinant of factorized real symmetric positive definite matrix
*/
nag_det_real_sym(order, n, a, pda, &d, &id, &fail);
if (fail.code != NE_NOERROR) {
printf("%s\n", fail.message);
exit_status = 3;
goto END;
}

printf("\nd = %12.5f  id = %12" NAG_IFMT "\n", d, id);
printf("Value of determinant = %12.5e\n", d * pow(2.0, id));

END:
NAG_FREE(a);

return exit_status;
}
```