```/* nag_lapacklin_dsgesv (f07acc) Example Program.
*
* Copyright 2020 Numerical Algorithms Group.
*
* Mark 27.1, 2020.
*/

#include <math.h>
#include <nag.h>
#include <stdio.h>

int main(void) {

/* Scalars */
Integer exit_status = 0;
Integer i, iter, j, n, nrhs, pda, pdb, pdx;

/* Arrays */
Integer *ipiv = 0;
double *a = 0, *b = 0, *x = 0;

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

INIT_FAIL(fail);

printf("nag_lapacklin_dsgesv (f07acc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n]", &n, &nrhs);
if (n < 0 || nrhs < 0) {
printf("Invalid n or nrhs\n");
exit_status = 1;
return exit_status;
}

pda = n;
#ifdef NAG_COLUMN_MAJOR
pdb = n;
pdx = n;
#define A(I, J) a[(J - 1) * pda + I - 1]
#define B(I, J) b[(J - 1) * pdb + I - 1]
order = Nag_ColMajor;
#else
pdb = nrhs;
pdx = nrhs;
#define A(I, J) a[(I - 1) * pda + J - 1]
#define B(I, J) b[(I - 1) * pdb + J - 1]
order = Nag_RowMajor;
#endif

/* Allocate memory */
if (!(a = NAG_ALLOC(n * n, double)) || !(b = NAG_ALLOC(n * nrhs, double)) ||
!(x = NAG_ALLOC(n * nrhs, double)) || !(ipiv = NAG_ALLOC(n, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Read A and B from data file */
for (i = 1; i <= n; i++)
for (j = 1; j <= n; j++)
scanf("%lf", &A(i, j));
scanf("%*[^\n] ");
for (i = 1; i <= n; i++)
for (j = 1; j <= nrhs; j++)
scanf("%lf", &B(i, j));
scanf("%*[^\n] ");

/* Solve the equations Ax = b for x  using nag_lapacklin_dsgesv (f07acc)
* Mixed precision real system solver.
*/
nag_lapacklin_dsgesv(order, n, nrhs, a, pda, ipiv, b, pdb, x, pdx, &iter,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_lapacklin_dsgesv (f07acc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Print solution using
* nag_file_print_matrix_real_gen (x04cac)
*/
fflush(stdout);
nag_file_print_matrix_real_gen(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n,
nrhs, x, pdx, "Solution(s)", 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen (x04cac).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Print pivot indices */
printf("\nPivot indices\n");
for (i = 0; i < n; i++)
printf("%11" NAG_IFMT "%s", ipiv[i], (i + 1) % 7 ? " " : "\n");
printf("\n");

END:
NAG_FREE(a);
NAG_FREE(b);
NAG_FREE(x);
NAG_FREE(ipiv);

return exit_status;
}

#undef A
#undef B
```