```/* nag_lone_fit (e02gac) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.1, 2017.
*/

#include <stdio.h>
#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nage02.h>

int main(void)
{
/* Scalars */
double resid, t, tol;
Integer exit_status, i, iter, m, rank, n, nplus2, pda;
NagError fail;
Nag_OrderType order;

/* Arrays */
double *a = 0, *b = 0, *x = 0;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J-1)*pda + I - 1]
order = Nag_ColMajor;
#else
#define A(I, J) a[(I-1)*pda + J - 1]
order = Nag_RowMajor;
#endif

INIT_FAIL(fail);

exit_status = 0;
printf("nag_lone_fit (e02gac) Example Program Results\n");

/* Skip heading in data file */
scanf("%*[^\n] ");

n = 3;
nplus2 = n + 2;
scanf("%" NAG_IFMT "%*[^\n] ", &m);
if (m > 0) {
/* Allocate memory */
if (!(a = NAG_ALLOC((m + 2) * nplus2, double)) ||
!(b = NAG_ALLOC(m, double)) || !(x = NAG_ALLOC(nplus2, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

if (order == Nag_ColMajor)
pda = m + 2;
else
pda = nplus2;

for (i = 1; i <= m; ++i) {
scanf("%lf%lf%*[^\n] ", &t, &b[i - 1]);
A(i, 1) = exp(t);
A(i, 2) = exp(-t);
A(i, 3) = 1.0;
}
tol = 0.0;
/* nag_lone_fit (e02gac).
* L_1-approximation by general linear function
*/
nag_lone_fit(order, m, a, b, nplus2, tol, x, &resid, &rank, &iter, &fail);
if (fail.code == NE_INT || fail.code == NE_INT_2 ||
fail.code == NE_TOO_MANY_ITER ||
fail.code == NE_NO_LICENCE) {
printf("Error from nag_lone_fit (e02gac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
else {
printf("\n");
printf("resid = %11.2e  Rank = %5" NAG_IFMT "  Iterations ="
" %5" NAG_IFMT "\n", resid, rank, iter);

printf("\n");
printf("Solution\n");

for (i = 1; i <= n; ++i)
printf("%10.4f", x[i - 1]);
printf("\n");
}
}

END:
NAG_FREE(a);
NAG_FREE(b);
NAG_FREE(x);

return exit_status;
}
```