I have an n-ary tree implementation consisting of a header file. I
include this ntree.hh file and an example code below called ntree.C.
All this seems to be working.
I have a problem with the following code called trouble.C. The probem
is nodes.push_back(node);
line. The error message I get is below. What is the cause for this? Do
I need a constructor? I am compiling it on Fedora.
Nandor
==================================== error message
g++ trouble.C
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/stl_construct.h:
In function 'void std::_Construct(_T1*, const _T2&) [with _T1 =
Tdata, _T2 = Tnode<Tdata>]':
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/stl_uninitialized.h:86:
instantiated from '_ForwardIterator
std::__uninitialized_copy_aux(_InputIterator, _InputIterator,
_ForwardIterator, __false_type) [with _InputIterator =
__gnu_cxx::__normal_iterator<Tnode<Tdata>*, std::vector<Tnode<Tdata>,
std::allocator<Tnode<Tdata> > > >, _ForwardIterator =
__gnu_cxx::__normal_iterator<Tnode<Tdata>*, std::vector<Tnode<Tdata>,
std::allocator<Tnode<Tdata> > > >]'
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/stl_uninitialized.h:113:
instantiated from '_ForwardIterator
std::uninitialized_copy(_InputIterator, _InputIterator,
_ForwardIterator) [with _InputIterator =
__gnu_cxx::__normal_iterator<Tnode<Tdata>*, std::vector<Tnode<Tdata>,
std::allocator<Tnode<Tdata> > > >, _ForwardIterator =
__gnu_cxx::__normal_iterator<Tnode<Tdata>*, std::vector<Tnode<Tdata>,
std::allocator<Tnode<Tdata> > > >]'
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/stl_uninitialized.h:254:
instantiated from '_ForwardIterator
std::__uninitialized_copy_a(_InputIterator, _InputIterator,
_ForwardIterator, std::allocator<_Tp>) [with _InputIterator =
__gnu_cxx::__normal_iterator<Tnode<Tdata>*, std::vector<Tnode<Tdata>,
std::allocator<Tnode<Tdata> > > >, _ForwardIterator =
__gnu_cxx::__normal_iterator<Tnode<Tdata>*, std::vector<Tnode<Tdata>,
std::allocator<Tnode<Tdata> > > >, _Tp = Tnode<Tdata>]'
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/vector.tcc:279:
instantiated from 'void std::vector<_Tp,
_Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename
_Alloc::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp =
Tnode<Tdata>, _Alloc = std::allocator<Tnode<Tdata> >]'
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/stl_vector.h:610:
instantiated from 'void std::vector<_Tp, _Alloc>::push_back(const
_Tp&) [with _Tp = Tnode<Tdata>, _Alloc = std::allocator<Tnode<Tdata>
]'
trouble.C:27: instantiated from here
/usr/lib/gcc/i386-redhat-linux/4.0.2/../../../../include/c++/4.0.2/bits/stl_construct.h:81:
error: no matching function for call to 'Tdata::Tdata(const
Tnode<Tdata>&)'
trouble.C:14: note: candidates are: Tdata::Tdata()
trouble.C:14: note: Tdata::Tdata(const Tdata&)
=============================================== code causing trouble
// trouble.C
#include <iostream>
#include "ntree.hh"
#include <vector>
/*
typedef struct {
string a;
string b;
} Tdata;
*/
struct Tdata {
string a;
string b;
};
typedef Tnode < Tdata > TNode;
main ()
{
TNode head, node;
make_head (head);
vector<TNode> nodes;
nodes.push_back(node);
}
=============================================== header file
// ntree.hh
#include <vector>
#include <string>
using namespace std;
// data and the arrows
template < class T > struct Tnode_
{
T data;
vector < Tnode_ * >ch;
Tnode_ *parentp;
};
// a Tnode is a pointer to a Tnode_ with member functions
template < class T > struct Tnode
{
Tnode_ < T > *p;
// is this node the head of the tree?
bool ishead ()
{
return NULL == p->parentp;
}
// get the data value of the node
T get ()
{
return p->data;
}
// set the data value of the node
void set (T a)
{
p->data = a;
}
// the n-th child node
Tnode child (int n)
{
Tnode node2;
node2.p = p->ch[n];
return node2;
}
// add a child node
void add_child ()
{
Tnode_<T> * chp;
chp = new Tnode_ < T >;
chp->parentp = p;
p->ch.push_back (chp);
}
// number of children
int Nchildren ()
{
return p->ch.size ();
}
// the first child node
Tnode begin ()
{
Tnode node2;
node2.p = p->ch.front ();
return node2;
}
// the last child node
Tnode end ()
{
Tnode node2;
node2.p = p->ch.back ();
return node2;
}
// the parent node
Tnode parent ()
{
Tnode node2;
node2.p = p->parentp;
return node2;
}
T *operator & ()
{
return &p->data;
}
};
// make a tree head and set node to this head
template < class T > void
make_head (Tnode < T > &node)
{
node.p = new Tnode_ < T >;
node.p->parentp = NULL;
}
// print the tree
template < class T > void
travel (Tnode < T > node, int level)
{
for (int i = 0; i < level; i++)
cout << " :";
cout << ". ";
cout << node.get () << "\n";
for (int i = 0; i < node.Nchildren (); i++)
travel (node.child (i), level + 1);
}
// cut a child
template < class T > void
cut_child (Tnode < T > node, int n)
{
Tnode<T> childnode = node.child (n);
while (childnode.Nchildren () > 0) {
cut_child (childnode, 0);
}
delete node.p->ch[n];
node.p->ch.erase (node.p->ch.begin () + n);
}
========================================= working example code
// ntree.C
#include <iostream>
#include "ntree.hh"
#include <vector>
typedef struct {
string a;
string b;
} Tdata;
typedef Tnode < Tdata > TNode;
main ()
{
TNode head, node;
vector<TNode> nodes;
nodes.push_back(node);
make_head (head);
node = head;
Tdata data;
data.a="one";
node.set (data);
node.add_child ();
node.add_child ();
node = node.end ();
data.a="three";
node.set (data);
node = node.parent ();
node = node.begin ();
data.a="two";
node.set (data);
node.add_child ();
node.add_child ();
node.add_child ();
node = node.begin ();
data.a="apple";
node.set (data);
node = node.parent ();
node = node.end ();
data.a="peach";
node.set (data);
node = node.parent ();
node = node.child (1);
data.a="banana";
node.set (data);
node.add_child ();
node = node.begin ();
data.a="cherry";
node.set (data);
travel (head, 0);
cout << "-----------\n";
data = node.get();
cout << data.a << "\n";
(*&node).a = "CHERRY";
while (! node.ishead()) {
node=node.parent();
data = node.get();
cout << data.a << "\n";
}
cout << "-----------\n";
cut_child(head,0);
travel(head, 0);
}
.
|
|
| User: "Daniel T." |
|
| Title: Re: n-ary tree |
22 Oct 2006 05:40:48 PM |
|
|
In article <1161553002.389381.196810@m73g2000cwd.googlegroups.com>,
wrote:
T *operator & ()
{
return &p->data;
}
Get rid of the above function.
--
There are two things that simply cannot be doubted, logic and perception.
Doubt those, and you no longer have anyone to discuss your doubts with,
nor any ability to discuss them.
.
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