NAG Library Manual, Mark 28.7
```/* nag_sum_chebyshev (c06dcc) Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
*
* Mark 28.7, 2022.
*/

#include <nag.h>

int main(void) {
/* Scalars */
Integer exit_status = 0, i, lx, n;
double xmax, xmin;
/* Arrays */
char sstr[30];
double *c = 0, *res = 0, *x = 0;
/* Nag Types */
Nag_Series s;
NagError fail;

INIT_FAIL(fail);

printf("nag_sum_chebyshev (c06dcc) Example Program Results\n");
/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "%*[^\n]%" NAG_IFMT "%*[^\n]", &n, &lx);

if (!(c = NAG_ALLOC(n, double)) || !(res = NAG_ALLOC(lx, double)) ||
!(x = NAG_ALLOC(lx, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 0; i < lx; i++)
scanf("%lf", &x[i]);
scanf("%*[^\n]");
scanf("%lf%lf%*[^\n]", &xmin, &xmax);
scanf("%29s%*[^\n]", sstr);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
s = (Nag_Series)nag_enum_name_to_value(sstr);
for (i = 0; i < n; i++)
scanf("%lf", &c[i]);

/* nag_sum_chebyshev (c06dcc).
* Evaluates a polynomial from its Chebyshev series representation.
*/
nag_sum_chebyshev(x, lx, xmin, xmax, c, n, s, res, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sum_chebyshev (c06dcc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

printf("\n%8s%16s\n", "x", "sum at x");
for (i = 0; i < lx; i++)
printf("%11.4f%13.4f\n", x[i], res[i]);

END:
NAG_FREE(c);
NAG_FREE(res);
NAG_FREE(x);

return exit_status;
}
```