```/* nag_zeros_real_poly (c02agc) Example Program.
*
* Copyright 2014 Numerical Algorithms Group.
*
* Mark 2, 1991.
*
* Mark 8 revised, 2004.
*/

#include <nag.h>
#include <stdio.h>
#include <math.h>
#include <nag_stdlib.h>
#include <nagc02.h>

int main(void)
{

Nag_Boolean scale;
Complex     *z = 0;
Integer     exit_status = 0, i, n, nroot;
NagError    fail;
double      *a = 0;

INIT_FAIL(fail);

printf("nag_zeros_real_poly (c02agc) Example Program Results\n");
/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%ld", &n);
if (n > 0)
{
scale = Nag_TRUE;
if (!(a = NAG_ALLOC(n+1, double)) ||
!(z = NAG_ALLOC(n, Complex)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
}
else
{
printf("Invalid n.\n");
exit_status = 1;
return exit_status;
}

for (i = 0; i <= n; i++)
scanf("%lf", &a[i]);
printf("\nDegree of polynomial = %4ld\n\n", n);

/* nag_zeros_real_poly (c02agc).
* Zeros of a polynomial with real coefficients
*/
nag_zeros_real_poly(n, a, scale, z, &fail);
if (fail.code != NE_NOERROR)
{
printf("Error from nag_zeros_real_poly (c02agc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

printf("Roots of polynomial\n\n");
nroot = 1;
while (nroot <= n)
{
if (z[nroot-1].im == 0.0)
{
printf("z = %13.4e\n", z[nroot-1].re);
nroot += 1;
}
else
{
printf("z = %13.4e   +/- %14.4e\n", z[nroot-1].re,
fabs(z[nroot-1].im));
nroot += 2;
}
}
END:
NAG_FREE(a);
NAG_FREE(z);
return exit_status;
}
```