FIXED: had the method twice in the header file
I get the following error when trying to compile my project
% make
g++ -o p4 testTree.o tree.o node.o check.o
Undefined first referenced
symbol in file
Tree::inTree(int) tree.o
ld: fatal: Symbol referencing errors. No output written to p4
collect2: ld returned 1 exit status
*** Error code 1
make: Fatal error: Command failed for target `p4'
Makefile
p4: testTree.o tree.o node.o check.o
g++ -o p4 testTree.o tree.o node.o check.o
testTree.o: testTree.cc tree.h node.h check.h
g++ -c -Wall -Werror testTree.cc
tree.o: tree.h tree.cc node.h check.h
g++ -c -Wall -Werror tree.cc
node.o: node.h node.cc check.h
g++ -c -Wall -Werror node.cc
check.o: check.h check.cc
g++ -c -Wall -Werror check.cc
clean:
rm -f *~ *.o p4
Relevant code from tree.cc and tree.h:
tree.cc
...
bool Tree::inTree(int k) const
{
return locate(k,root) != NULL;
}
...
tree.h
#ifndef TREE_H
#define TREE_H
#include "node.h"
#include "check.h"
using namespace std;
class Tree
{
private:
Node *root;
public:
Tree();
Tree(const Tree & t);
const Tree & operator=(const Tree &t);
friend ostream & operator<<(ostream &out, const Tree &t);
bool inTree(int k) const;
double & operator[](int k);
double & operator[](int k) const;
~Tree();
bool inTree(int index);
private:
Node * locate(int k, Node *rt) const;
ostream & display(ostream &out, Node *r, int dir=Node::L) const;
void add(int k, Node*&r);
void kill(Node *&rt);
void copy(Node *rt, Node *&newRt);
};
#endif
I get the feeling that it's something really simple, but I can't seem to figure it out.
2 Answers
The message you are getting actually comes from the linker, not from the compiler.
One of your member functions, bool Tree::inTree(int index);, is correctly declared and defined as a const member function:
// Declaration in tree.h
bool inTree(int index) const;
// Definition in tree.cc
bool Tree::inTree(int k) const
// ^^^^^
However, in tree.h you also define this non-const overload of inTree():
// Declaration in tree.h, definition (supposedly) nowhere
bool Tree::inTree(int k)
For which no definition is provided. This is what the linker complains about.
Here is your error:
bool Tree::inTree(int k) const
{
return locate(k,root) != NULL;
}
in your .h you define
bool inTree(int);
This is a difference!
