NAG Library Manual, Mark 27.2
Interfaces:  FL   CL   CPP   AD
```/* F07AD_P0W_F C++ Header Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
* Mark 27.2, 2021.
*/

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

int main(void)
{
int     exit_status = 0;
void *  ad_handle   = 0;
Integer ifail       = 0;

cout << "F07AD_P0W_F C++ Header Example Program Results\n\n";
// Skip heading in data file
string mystr;
getline(cin, mystr);

// Read problem size and number of right-hand-sides
Integer n;
cin >> n;

// Allocate arrays containing A and its factorized form, B
// and the solution X.
double * a = 0, *work = 0;
Integer *ipiv  = 0;
Integer  lwork = 64 * n;
a              = new double[n * n];
work           = new double[lwork];
ipiv           = new Integer[n];

// Read the matrix A, register and copy
for (int i = 0; i < n; ++i)
{
for (int j = 0; j < n; ++j)
{
Integer k = i + j * n;
cin >> a[k];
}
}

// Print matrix A
cout << endl;
NagError fail;
INIT_FAIL(fail);
x04cac(Nag_ColMajor, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, n, "  A", 0,
&fail);

// Factorize the matrix A
ifail = 0;

// Invert A
ifail = 0;
nag::ad::f07aj(ad_handle, n, a, n, ipiv, work, lwork, ifail);

// Print Inverse
cout << endl;
x04cac(Nag_ColMajor, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, n,
"  Inverse", 0, &fail);

delete[] a;
delete[] work;
delete[] ipiv;
return exit_status;
}
```