NAG Library Manual, Mark 28.5
```/* E04DG_P0W_F C++ Header Example Program.
*
* Copyright 2022 Numerical Algorithms Group.
* Mark 28.5, 2022.
*/

#include <iostream>
#include <math.h>
#include <nag.h>
#include <nagx02.h>
#include <stdio.h>
#include <string>
using namespace std;

int main()
{
int    exit_status = 0;
double objf;
cout << "E04DG_P0W_F C++ Header Example Program Results\n\n";

Integer           ifail = 0;

// Read problem parameters and register for differentiation
// Skip first line of data file
string mystr;
getline(cin, mystr);

Integer n;
cin >> n;

// passive routine fixed length array arguments
Integer       iwsav[610];
double        ruser[1], rwsav[475];
char          cwsav[1];
logical       lwsav[120];
const Charlen name_l = 6, cwsav_l = 1;

// passive routine variable length arrays
Integer *iwork = 0;
double * x = 0, *x_in = 0, *objgrd = 0, *work = 0;

iwork  = new Integer[n + 1];
x      = new double[n];
x_in   = new double[n];
objgrd = new double[n];
work   = new double[13 * n];

for (int i = 0; i < n; i++)
{
cin >> x[i];
}

Integer &               mode,
const Integer &         n,
const double *x,
double &     objf,
double *objgrd,
const Integer &         nstate)
{
// dco/c++ used here to perform AD of objfun
double x1, x2, y1, y2, expx1;

x1    = x[0];
x2    = x[1];
expx1 = exp(x1);
y1    = 2.0 * x1;
y1    = y1 + x2;
y2    = x2 + 1.0;
x1    = y1 * y1;
x2    = y2 * y2;
x1    = x1 + x2;
objf  = expx1 * x1;

if (mode == 2)
{
y2        = y1 + y2;
y2        = 2.0 * y2;
y1        = 4.0 * y1;
y1        = expx1 * y1;
objgrd[0] = y1 + objf;
objgrd[1] = expx1 * y2;
}
};
// Initialize sav arrays
ifail = 0;
nag::ad::e04wb("E04DGA", cwsav, 1, lwsav, 120, iwsav, 610, rwsav, 475, ifail);

// Solve the problem
Integer iter;
ifail = 0;
nag::ad::e04dg(ad_handle, n, objfun, iter, objf, objgrd, x, iwork, work, lwsav, iwsav, rwsav, ifail);

// Primal results
cout.setf(ios::scientific, ios::floatfield);
cout.precision(3);
cout << "\n Objective value = ";
cout.width(12);
cout << objf;
cout << "\n Solution point  = ";
for (int i = 0; i < n; i++)
{
cout.width(12);
cout << x[i];
}

cout << "\n Estim gradient  = ";
for (int i = 0; i < n; i++)
{
cout.width(12);
cout << objgrd[i];
}
cout << endl;

delete[] iwork;
delete[] x;
delete[] x_in;
delete[] objgrd;
delete[] work;
return exit_status;
}
```