我遇到了一些链接器错误，我无法解决这些问题。我只是有一个.h文件和一个不会编译成可执行文件的.cc文件 除了makefile之外，我不会发布我的所有代码：
# Compiler variables
CCFLAGS = -Wall
# Rule to link object code files to create executable file
assignment5.exe: assignment5.cc
g++ -Wall -g -std=c++11 assignment5.cc assignment5.h -o assignment5.exe
clean:
rm assignment5.exe
我在同一目录下有assignment5.h和assignment5.cc，在运行'make'时出现此错误：
assignment5.cc:113: undefined reference to `binTree::inorder(void (*)(int))'
assignment5.cc:116: undefined reference to `binTree::preorder(void (*)(int))'
assignment5.cc:119: undefined reference to `binTree::postorder(void (*)(int))'
如果有人能帮助我，我将永远感激不尽 编辑： 那些问的代码 .h档案：
#ifndef ASSIGNMENT5
#define ASSIGNMENT5
class binTree; class BST;
class Node {
public:
// the value
int data;
// the left and right
Node * left;
Node * right;
// the constructor
Node(int data)
{
// set the data
this->data = data;
// set left and right to null
this->right = nullptr;
this->left = nullptr;
}
};
class binTree
{
public:
binTree();
virtual void insert( int ); //Inserts a node into the tree
unsigned height() const; //Returns height of the tree
unsigned size() const; //Returns size of the tree
void inorder( void(*)(int) ); //Inorder traversal of tree
void preorder( void(*)(int) ); //Preorder traversal
void postorder( void(*)(int) ); //Postorder traversal
protected:
Node* root; //root of the tree
private:
void insert( Node*&, int ); //Private version of insert()
unsigned height( Node* ) const; //Private version of height
unsigned size( Node* ) const; //Private version of size()
void inorder( Node*, void(*)(int) ); //Private version of inorder()
void preorder( Node*, void(*)(int) ); //Private version of preorder()
void postorder( Node*, void(*)(int) ); //Private version of postorder()
};
#endif
.cc文件：
#include "assignment5.h"
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
using namespace std;
const int MAX_SIZE = 40;
const int MAX_COUNT = 40;
const int WIDTH = 5;
const int ROW_SIZE = 8;
int mcount = 0;
int rcount = 0;
void display(int d)
{
if (mcount < MAX_COUNT) {
cout << setw(WIDTH) << d;
mcount++;
rcount++;
if (rcount == ROW_SIZE) {
cout << endl;
rcount = 0;
}
}
}
binTree::binTree()
{
// set the root to null pointer
root = nullptr;
}
void binTree::insert( int v ) //Inserts a node into the tree
{
// insert this value into the root
insert(root,v);
}
unsigned binTree::height() const //Returns height of the tree
{
// return the height of this tree
return height(root);
}
unsigned binTree::size() const //Returns size of the tree
{
// return the size
return size(root);
}
void binTree::inorder( void(*)(int) p ) //Inorder traversal of tree
{
// use the local inorder
inorder(root, p);
}
void binTree::preorder( void(*)(int) p ) //Preorder traversal
{
// use the local preorder
inorder(root, p);
}
void binTree::postorder( void(*)(int) p ) //Postorder traversal
{
// use the local inorder
postorder(root, p);
}
void binTree::insert( Node*& node, int n ) //Private version of insert()
{
// if this is null, create new node
if( node == nullptr )
{
// create new node
node = new Node(n);
}
// if node is less or more
if( n < node->data )
{
// go left
insert(node->left,n);
}
else if( n > node->data )
{
// go right
insert(node->right, n);
}
}
unsigned binTree::height( Node* node ) const //Private version of height
{
// if this is null, return 0
if( node == nullptr )
return 0;
// left height and right height
unsigned leftHeight = 0;
unsigned rightHeight = 0;
// check if left height
if( node->left != nullptr )
leftHeight = height( node->left );
// right height
if( node->right != nullptr )
rightHeight = height( node->right );
// return max
if( leftHeight > rightHeight )
return leftHeight + 1;
else
return rightHeight+1;
}
unsigned binTree::size( Node* node) const //Private version of size()
{
// if this is null
if( node == nullptr )
return 0;
// return size
return 1 + size(node->left) + size(node->right);
}
#define BINTREE_MAIN
#ifdef BINTREE_MAIN
int main() {
vector<int> v(MAX_SIZE);
for (int i=1; i<MAX_SIZE; i++)
v[i] = i;
random_shuffle( v.begin(), v.end());
binTree bt;
vector<int>::iterator it;
for (it=v.begin(); it!=v.end(); it++)
bt.insert( *it );
cout << "Height: " << bt.height() << endl;
cout << "Size: " << bt.size() << endl;
cout << "In order traverse (displaying first " << MAX_COUNT << " numbers): " << endl;
mcount = rcount = 0;
bt.inorder( display );
cout << "\n\nPre order traverse (displaying first " << MAX_COUNT << " numbers): " << endl;
mcount = rcount = 0;
bt.preorder( display );
cout << "\n\nPost order traverse (displaying first " << MAX_COUNT << " numbers): " << endl;
mcount = rcount = 0;
bt.postorder( display );
cout << endl;
return 0;
}
#endif
答案 0 :(得分：1)
Makefile不是（唯一的）责备。你的例子充满了问题。对于初学者来说，它不是一个完整的例子，因为一半的方法没有定义，只是声明了，当你试图构建一个可执行文件时，没有main()，甚至是虚拟的，而不是一个目标文件。这样一个不完整的例子真的很难帮到你。
而你似乎并没有说出全部真相。我的g++调用甚至更早，在这一行：
void inorder( void(*)(int) ); //Inorder traversal of tree
expected primary-expression before ‘void’
您是否尝试声明一个接受参数的方法，该参数是一个指向函数的指针（int）？您需要了解C ++中syntax的含义。
makefile中的配方行也存在缺陷：您不需要将头文件传递给编译器，当您在.cc文件中#include时，它们会自动包含在内。您的构建行应类似于：
g++ $(CCFLAGS) -g -std=c++11 assignment5.cc -o assignment5.o
答案 1 :(得分：0)
您尚未实施私人功能：
void inorder( Node*, void(*)(int) ); //Private version of inorder()
void preorder( Node*, void(*)(int) ); //Private version of preorder()
void postorder( Node*, void(*)(int) ); //Private version of postorder()
答案 2 :(得分：0)
你有两个bintree课程。首先修复并报告。
class binTree; class BST;
class Node {
....
};
....
class binTree {
};