```/* nag_sparse_nsym_sol (f11dec) Example Program.
*
* Copyright 2014 Numerical Algorithms Group.
*
* Mark 5, 1998.
*/

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nag_string.h>
#include <nagf11.h>

int main(void)
{
double                  *a = 0, *b = 0, *x = 0;
double                  omega;
double                  rnorm;
double                  tol;
Integer                 exit_status = 0;
Integer                 *icol = 0, *irow = 0;
Integer                 i, m, n;
Integer                 maxitn, itn;
Integer                 nnz;
char                    nag_enum_arg[40];
Nag_SparseNsym_Method   method;
Nag_SparseNsym_PrecType precon;
Nag_Sparse_Comm         comm;
NagError                fail;

INIT_FAIL(fail);

printf("nag_sparse_nsym_sol (f11dec) Example Program Results\n");
/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%ld%*[^\n]", &n);
scanf("%ld%*[^\n]", &nnz);
scanf("%39s", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
method = (Nag_SparseNsym_Method) nag_enum_name_to_value(nag_enum_arg);
scanf("%39s%*[^\n]", nag_enum_arg);
precon = (Nag_SparseNsym_PrecType) nag_enum_name_to_value(nag_enum_arg);
scanf("%lf%*[^\n]", &omega);
scanf("%ld%lf%ld%*[^\n]", &m, &tol, &maxitn);

x = NAG_ALLOC(n, double);
b = NAG_ALLOC(n, double);
a = NAG_ALLOC(nnz, double);
irow = NAG_ALLOC(nnz, Integer);
icol = NAG_ALLOC(nnz, Integer);
if (!irow || !icol || !a || !x || !b)
{
printf("Allocation failure\n");
exit_status = 1;
goto END;
}

/* Read the matrix a */

for (i = 1; i <= nnz; ++i)
scanf("%lf%ld%ld%*[^\n]", &a[i-1], &irow[i-1],
&icol[i-1]);

/* Read right-hand side vector b and initial approximate solution x */

for (i = 1; i <= n; ++i)
scanf("%lf", &b[i-1]);
scanf("%*[^\n]");

for (i = 1; i <= n; ++i)
scanf("%lf", &x[i-1]);
scanf("%*[^\n]");

/* Solve Ax = b using nag_sparse_nsym_sol (f11dec) */

/* nag_sparse_nsym_sol (f11dec).
* Solver with no Jacobi/SSOR preconditioning (nonsymmetric)
*/
nag_sparse_nsym_sol(method, precon, n, nnz, a, irow, icol, omega, b, m, tol,
maxitn, x, &rnorm, &itn, &comm, &fail);

printf("%s%10ld%s\n", "Converged in", itn, " iterations");
printf("%s%16.3e\n", "Final residual norm =", rnorm);

/* Output x */
printf("           x\n");
for (i = 1; i <= n; ++i)
printf(" %16.6e\n", x[i-1]);

END:
NAG_FREE(irow);
NAG_FREE(icol);
NAG_FREE(a);
NAG_FREE(x);
NAG_FREE(b);

return exit_status;
}
```