```/* nag_ztrttp (f01vbc) Example Program.
*
* Copyright 2014 Numerical Algorithms Group.
*
* Mark 25, 2014.
*/

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf01.h>
#include <nagx04.h>

int main(void)
{
/* Scalars */
Integer        exit_status = 0, inc1 = 1, indent = 0, ncols = 80, i, j, pda;
Integer        lenap, mx, n, nx;
/* Arrays */
Complex        *a = 0, *ap = 0;
char           nag_enum_arg[40], form[] = "%5.2f";
/* Nag Types */
Nag_OrderType  order;
Nag_UploType   uplo;
Nag_MatrixType matrix;
NagError       fail;

#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[J*pda + I]
order = Nag_ColMajor;
#define KU(I,J,N) (I + J*(J+1)/2)
#define KL(I,J,N) (J*(N-1) - J*(J-1)/2 + I)
#else
#define A(I, J) a[I*pda + J]
order = Nag_RowMajor;
#define KL(I,J,N) (J + I*(I+1)/2)
#define KU(I,J,N) (I*(N-1) - I*(I-1)/2 + J)
#endif

INIT_FAIL(fail);

printf("nag_ztrttp (f01vbc) Example Program Results\n\n");
/* Skip heading in data file*/
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n] ", &n);
scanf("%39s  %*[^\n] ", nag_enum_arg);
pda = n;
lenap = (n * (n + 1))/2;
if (!(a = NAG_ALLOC(pda*n, Complex)) || !(ap = NAG_ALLOC(lenap, Complex))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);
/* Read a triangular matrix of order n. */
if (uplo==Nag_Upper) {
for (i = 0; i < n; i++) {
for (j = 0; j < n; j++) scanf(" ( %lf , %lf ) ", &A(i, j).re,
&A(i, j).im);
}
} else {
for (i = 0; i < n; i++) {
for (j = 0; j <= i; j++) scanf(" ( %lf , %lf ) ", &A(i, j).re,
&A(i, j).im);
}
}

/* Print the unpacked matrix. */
matrix = (uplo == Nag_Upper ? Nag_UpperMatrix : Nag_LowerMatrix);
/* nag_gen_complx_mat_print_comp (x04dbc).
* Print complex general matrix (comprehensive).
*/
fflush(stdout);
nag_gen_complx_mat_print_comp(order, matrix, Nag_NonUnitDiag, n, n, a, pda,
Nag_BracketForm, form, "Unpacked Matrix A:",
Nag_IntegerLabels, NULL, Nag_IntegerLabels,
NULL, ncols, indent, NULL, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
printf("\n");

/* Convert to  triangular matrix from full to packed vector form using
* nag_ztrttp (f01vbc).
*/
nag_ztrttp(order, uplo, n, a, pda, ap, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_ztrttp (f01vbc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Print the packed vector */
if (order==Nag_RowMajor) {
mx = inc1;
nx = lenap;
} else {
mx = lenap;
nx = inc1;
}

fflush(stdout);
nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, mx,
nx, ap, lenap, Nag_BracketForm, form,
"Packed Array AP:", Nag_IntegerLabels, NULL,
Nag_NoLabels, NULL, ncols, indent, NULL,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 1;
}
printf("\n");

/* Print the packed vector*/
printf(" Packed Array AP (printed using KL/KU macros):\n\n");
for (i = 0; i < n; i++) {
if (uplo==Nag_Upper) {
printf("  ");
for (j = 0; j < i; j++) printf("%15s"," ");
for (j = i; j < n; j++) printf("  (%5.2f,%5.2f)", ap[KU(i,j,n)].re,
ap[KU(i,j,n)].im);
} else {
for (j = 0; j <= i; j++) printf("  (%5.2f,%5.2f)", ap[KU(i,j,n)].re,
ap[KU(i,j,n)].im);
}
printf("\n");
}

END:
NAG_FREE(a);
NAG_FREE(ap);
return exit_status;
}
```