```/* nag_lapacklin_dppequ (f07gfc) Example Program.
*
* Copyright 2020 Numerical Algorithms Group.
*
* Mark 27.1, 2020.
*/
#include <nag.h>
#include <stdio.h>

int main(void) {

/* Scalars */
double amax, big, scond, small;
Integer exit_status = 0, i, j, n;

/* Arrays */
double *ap = 0, *s = 0;
char nag_enum_arg[40];

/* Nag Types */
NagError fail;
Nag_OrderType order;
Nag_UploType uplo;

#ifdef NAG_COLUMN_MAJOR
#define A_UPPER(I, J) ap[J * (J - 1) / 2 + I - 1]
#define A_LOWER(I, J) ap[(2 * n - J) * (J - 1) / 2 + I - 1]
order = Nag_ColMajor;
#else
#define A_LOWER(I, J) ap[I * (I - 1) / 2 + J - 1]
#define A_UPPER(I, J) ap[(2 * n - I) * (I - 1) / 2 + J - 1]
order = Nag_RowMajor;
#endif
INIT_FAIL(fail);

printf("nag_lapacklin_dppequ (f07gfc) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "%*[^\n]", &n);
if (n < 0) {
printf("Invalid n\n");
exit_status = 1;
goto END;
}
scanf(" %39s%*[^\n]", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
uplo = (Nag_UploType)nag_enum_name_to_value(nag_enum_arg);

/* Allocate memory */
if (!(ap = NAG_ALLOC(n * (n + 1) / 2, double)) ||
!(s = NAG_ALLOC(n, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read the upper or lower triangular part of the matrix A from data file */
if (uplo == Nag_Upper)
for (i = 1; i <= n; ++i)
for (j = i; j <= n; ++j)
scanf("%lf", &A_UPPER(i, j));
else if (uplo == Nag_Lower)
for (i = 1; i <= n; ++i)
for (j = 1; j <= i; ++j)
scanf("%lf", &A_LOWER(i, j));
scanf("%*[^\n]");

/* Print the matrix A using nag_file_print_matrix_real_packed (x04ccc). */
fflush(stdout);
nag_file_print_matrix_real_packed(order, uplo, Nag_NonUnitDiag, n, ap,
"Matrix A", 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_packed (x04ccc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
printf("\n");

/* Compute diagonal scaling factors using nag_lapacklin_dppequ (f07gfc). */
nag_lapacklin_dppequ(order, uplo, n, ap, s, &scond, &amax, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_dppequ (f07gfc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Print scond, amax and the scale factors */
printf("scond = %10.1e, amax = %10.1e\n\n", scond, amax);
printf("Diagonal scaling factors\n");
for (i = 0; i < n; ++i)
printf("%11.1e%s", s[i], i % 7 == 6 ? "\n" : " ");
printf("\n\n");

/* Compute values close to underflow and overflow using
* nag_machine_real_safe (x02amc), nag_machine_precision (x02ajc) and
* nag_machine_model_base (x02bhc)
*/
small =
nag_machine_real_safe / (nag_machine_precision * nag_machine_model_base);
big = 1. / small;
if (scond < 0.1 || amax < small || amax > big) {
/* Scale A */
if (uplo == Nag_Upper)
for (j = 1; j <= n; ++j)
for (i = 1; i <= j; ++i)
A_UPPER(i, j) *= s[i - 1] * s[j - 1];
else
for (j = 1; j <= n; ++j)
for (i = j; i <= n; ++i)
A_LOWER(i, j) *= s[i - 1] * s[j - 1];

/* Print the scaled matrix using nag_file_print_matrix_real_packed (x04ccc).
*/
fflush(stdout);
nag_file_print_matrix_real_packed(order, uplo, Nag_NonUnitDiag, n, ap,
"Scaled matrix", 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_packed (x04ccc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
}
END:
NAG_FREE(ap);
NAG_FREE(s);

return exit_status;
}

#undef A_UPPER
#undef A_LOWER
```