```/* nag_dtprfs (f07uhc) Example Program.
*
* NAGPRODCODE Version.
*
* Copyright 2016 Numerical Algorithms Group.
*
* Mark 26, 2016.
*/

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf07.h>
#include <nagx04.h>

int main(void)
{
/* Scalars */
Integer ap_len, i, j, n, nrhs, berr_len, ferr_len;
Integer pdb, pdx;
Integer exit_status = 0;
Nag_UploType uplo;
NagError fail;
Nag_OrderType order;
/* Arrays */
char nag_enum_arg[40];
double *ap = 0, *b = 0, *berr = 0, *ferr = 0, *x = 0;

#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]
#define B(I, J)       b[(J-1)*pdb + I - 1]
#define X(I, J)       x[(J-1)*pdx + 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]
#define B(I, J)       b[(I-1)*pdb + J - 1]
#define X(I, J)       x[(I-1)*pdx + J - 1]
order = Nag_RowMajor;
#endif

INIT_FAIL(fail);

printf("nag_dtprfs (f07uhc) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &n, &nrhs);
berr_len = nrhs;
ferr_len = nrhs;
ap_len = n * (n + 1) / 2;
#ifdef NAG_COLUMN_MAJOR
pdb = n;
pdx = n;
#else
pdb = nrhs;
pdx = nrhs;
#endif

/* Allocate memory */
if (!(ap = NAG_ALLOC(ap_len, double)) ||
!(b = NAG_ALLOC(n * nrhs, double)) ||
!(berr = NAG_ALLOC(berr_len, double)) ||
!(ferr = NAG_ALLOC(ferr_len, double)) ||
!(x = NAG_ALLOC(n * nrhs, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read A and B from data file, and copy B to X */
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);

if (uplo == Nag_Upper) {
for (i = 1; i <= n; ++i) {
for (j = i; j <= n; ++j)
scanf("%lf", &A_UPPER(i, j));
}
scanf("%*[^\n] ");
}
else {
for (i = 1; i <= n; ++i) {
for (j = 1; j <= i; ++j)
scanf("%lf", &A_LOWER(i, j));
}
scanf("%*[^\n] ");
}
for (i = 1; i <= n; ++i) {
for (j = 1; j <= nrhs; ++j)
scanf("%lf", &B(i, j));
}
scanf("%*[^\n] ");
for (i = 1; i <= n; ++i) {
for (j = 1; j <= nrhs; ++j)
X(i, j) = B(i, j);
}
/* Compute solution in the array X */
/* nag_dtptrs (f07uec).
* Solution of real triangular system of linear equations,
* multiple right-hand sides, packed storage
*/
nag_dtptrs(order, uplo, Nag_NoTrans, Nag_NonUnitDiag, n,
nrhs, ap, x, pdx, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_dtptrs (f07uec).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Compute backward errors and estimated bounds on the */
/* forward errors */

/* nag_dtprfs (f07uhc).
* Error bounds for solution of real triangular system of
* linear equations, multiple right-hand sides, packed
* storage
*/
nag_dtprfs(order, uplo, Nag_NoTrans, Nag_NonUnitDiag, n,
nrhs, ap, b, pdb, x, pdx, ferr, berr, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_dtprfs (f07uhc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Print solution */

printf("\n");
/* nag_gen_real_mat_print (x04cac).
* Print real general matrix (easy-to-use)
*/
fflush(stdout);
nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs,
x, pdx, "Solution(s)", 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
printf("\nBackward errors (machine-dependent)\n");

for (j = 1; j <= nrhs; ++j)
printf("%11.1e%s", berr[j - 1], j % 7 == 0 ? "\n" : " ");
printf("\nEstimated forward error bounds " "(machine-dependent)\n");
for (j = 1; j <= nrhs; ++j)
printf("%11.1e%s", ferr[j - 1], (j % 7 == 0 || j == nrhs) ? "\n" : " ");
END:
NAG_FREE(ap);
NAG_FREE(b);
NAG_FREE(berr);
NAG_FREE(ferr);
NAG_FREE(x);

return exit_status;
}
```