NAG Library Manual, Mark 27.2
```/* E02DE_P0W_F C++ Header Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
* Mark 27.2, 2021.
*/

#include <dco.hpp>
#include <iostream>
#include <math.h>
#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <string>
using namespace std;

int main(void)
{
// Scalars
int exit_status = 0;

cout << "E02DE_P0W_F C++ Header Example Program Results\n\n";

// Skip first line of data file
string mystr;
getline(cin, mystr);
// Read number of x and y data points
Integer mx, my;
cin >> mx;
cin >> my;

// Allocate arrays for data and interpolant
double * x = 0, *lamda = 0, *y = 0, *mu = 0, *f = 0, *c = 0, *wrk = 0;
double * dx = 0, *dy = 0, *df = 0;
Integer *iwrk = 0;
Integer  lwrk = (my + 6) * (mx + 6);
x             = new double[mx];
y             = new double[my];
lamda         = new double[mx + 4];
mu            = new double[my + 4];
f             = new double[my * mx];
c             = new double[my * mx];
wrk           = new double[lwrk];
dx            = new double[mx];
dy            = new double[my];
df            = new double[my * mx];
iwrk          = new Integer[lwrk];

for (int i = 0; i < mx; i++)
{
double xr;
cin >> xr;
x[i] = xr;
}
for (int i = 0; i < my; i++)
{
double yr;
cin >> yr;
y[i] = yr;
}
for (int i = 0; i < my; i++)
{
double fr;
for (int j = 0; j < mx; j++)
{
Integer k = j * my + i;
cin >> fr;
f[k] = fr;
}
}

// Call the passive routine
Integer px, py;
Integer ifail     = 0;
nag::ad::e01da(ad_handle, mx, my, x, y, f, px, py, lamda, mu, c, wrk, ifail);

const Integer m = 1;
double        tx[m], ty[m], ff[m];
tx[0] = 1.4;
ty[0] = 0.5;

ifail = 0;
nag::ad::e02de(ad_handle, m, px, py, tx, ty, lamda, mu, c, ff, wrk, iwrk,
ifail);

cout << "\n Interpolant evaluated at x = " << tx[0];
cout << " and y = " << ty[0];
cout.precision(5);
cout << "\n Value of interpolant        = ";
cout << ff[0] << endl;

delete[] x;
delete[] y;
delete[] lamda;
delete[] mu;
delete[] f;
delete[] c;
delete[] wrk;
delete[] dx;
delete[] dy;
delete[] df;
delete[] iwrk;
return exit_status;
}
```