上面的代码有一个链接。关键是要创建一个方法来计算二叉树中的节点，然后创建两个也计算节点的方法，一个用于树的每一侧。我的问题是如何调用方法来计算节点。
我的问题是如何调用我的countNodes方法。我不知道它在寻找什么样的论点。
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <istream>
#include <string>
#include <cstdlib>
using namespace std;
template <class datatype>
class treenode{
public:
datatype data;
string qa;
treenode<datatype> *lchild, *rchild;
};
template<class datatype>
class btree{
private:
treenode<datatype> *root, *current;
public:
btree();
bool tree_empty(void);
void insertdata(datatype x); //call from main program to insert data
void inserttree(treenode<datatype> *&p, datatype d);
void inorder(treenode<datatype> *p);
void printinorder(void);//call from main program
void preorder(treenode<datatype> *p);
void printpreorder(void);//call from main program
void postorder(treenode<datatype> *p);
void printpostorder(void);//call from main program
void deletevalue(datatype v);
void deltree(datatype val, treenode<datatype> *&p);
treenode<datatype>* findmin(treenode<datatype> *p);
void inserttree2(treenode<datatype> *&p, datatype d, string qas);
void insertdata2(datatype x, string a);
void yesno(void);
int countNodes(treenode<datatype> *p);
};
template<class datatype>
btree<datatype>::btree(){
root =NULL;
};
template<class datatype>
bool btree<datatype>::tree_empty(){
bool x = true;
if(root == NULL){
x = true;
}else{
x = false;
}
return x;
};
template<class datatype>
void btree<datatype>::insertdata(datatype x){
inserttree(root,x);
};
template<class datatype>
void btree<datatype>::inserttree(treenode<datatype> *&p, datatype d){
if(p == NULL){
p = new treenode<datatype>;
p->data = d;
p->lchild = NULL;
p->rchild = NULL;
}else{
if(p->data > d)
inserttree(p->lchild,d);
else
inserttree(p->rchild,d);
}
};
template<class datatype>
void btree<datatype>::inorder(treenode<datatype> *p){
if(p!= NULL){
inorder(p->lchild);
cout<< p->data << " ";
inorder(p->rchild);
}
};
template<class datatype>
void btree<datatype>::printinorder(void){
inorder(root);
};
template<class datatype>
void btree<datatype>::preorder(treenode<datatype> *p){
if(p!= NULL){
cout<< p->data << " ";
preorder(p->lchild);
preorder(p->rchild);
}
};
template<class datatype>
void btree<datatype>::printpreorder(void){
preorder(root);
};
template<class datatype>
void btree<datatype>::postorder(treenode<datatype> *p){
if(p!= NULL){
postorder(p->lchild);
postorder(p->rchild);
cout<< p->data << " ";
}
};
template<class datatype>
void btree<datatype>::printpostorder(void){
postorder(root);
};
template<class datatype>
void btree<datatype>::deletevalue(datatype v){
deltree(v,root);
};
template<class datatype>
void btree<datatype>::deltree(datatype val, treenode<datatype> *&p){
treenode<datatype> *buff;
if(p != NULL)
if(val < p->data)
deltree(val,p->lchild);
else
if(val > p->data)
deltree(val, p->rchild);
else
if(p->lchild == NULL && p->rchild == NULL)
p= NULL;
else
if(p->lchild == NULL)
p= p->rchild;
else
if(p->rchild == NULL)
p = p->lchild;
else
{
buff = findmin(p->rchild);
buff->lchild = p->lchild;
p = p->rchild;
}
};
template<class datatype>
void btree<datatype>::inserttree2(treenode<datatype> *&p, datatype d, string qas){
if(p ==NULL){
p = new treenode<datatype>;
p->data = d;
p->qa = qas;
p->lchild = NULL;
p->rchild = NULL;
}else{
if(p->data > d)
inserttree2(p->lchild,d,qas);
else
inserttree2(p->rchild,d,qas);
}
};
template<class datatype>
void btree<datatype>::insertdata2(datatype x, string a){
inserttree2(root,x,a);
};
template<class datatype>
void btree<datatype>::yesno(void){
current = root;
bool solved = false;
char c;
cout<<current->qa<<endl;
while(!solved){
cout<<"Enter a Y or N";
cin>> c;
if(c == 'Y' ||c == 'N'){
if(c == 'Y'){
current = current->lchild;
}
if(c == 'N'){
current = current->rchild;
}
cout<<current->qa<<endl;
if(current->lchild == NULL){
solved = true;
cout<<"You have your answer "<<endl;
}
}
}
};
template<class datatype>
treenode<datatype>* btree<datatype>::findmin(treenode<datatype> *p){
if(p->lchild == NULL)
return (p);
else
return(findmin(p->lchild));
};
template<class datatype>
int btree<datatype>::countNodes(treenode<datatype> *p){
int count = 1;
if ( p == NULL ){
return 0;
}else{
int count = 1; /
count += countNodes(p->lchild);
count += countNodes(p->rchild);
} /
return count;
};
int _tmain(int argc, _TCHAR* argv[])
{
btree<int> genesistree;
int datavalues,
deletevalues,
addvalues,
newdata,
olddata,
newnewdata,
ifstatement,
c,
*p;
bool flag;
genesistree.insertdata(14);
genesistree.insertdata(2);
genesistree.insertdata(34);
genesistree.insertdata(41);
genesistree.insertdata(12);
/*
if(genesistree.tree_empty()){
cout<<"The list is empty"<<endl;
}else{
cout<<"The list is not empty"<<endl;
}
cout<<""<<endl;
cout<<"Enter the ammount of data values for the tree"<<endl;
cin>>datavalues;
cout<<""<<endl;
for(c = datavalues, c >= 0; c--;){
cout<<"Enter a datavalue for the tree"<<endl;
cin>>newdata;
genesistree.insertdata(newdata);
cout<<""<<endl;
}
cout<<""<<endl;
if(genesistree.tree_empty()){
cout<<"The list is empty"<<endl;
}else{
cout<<"The list is not empty"<<endl;
}
cout<<""<<endl;
cout<<"Print Preorder"<<endl;
genesistree.printpreorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Print in order"<<endl;
genesistree.printinorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Print Postorder"<<endl;
genesistree.printpostorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Enter the ammount of datavalues you would like to delete"<<endl;
cin>>deletevalues;
cout<<""<<endl;
if(deletevalues < datavalues){
for(c = deletevalues, c >= 0; c--;){
cout<<"Enter a datavalue to delete in the tree"<<endl;
cin>>olddata;
genesistree.deletevalue(olddata);
}
}else{
if(deletevalues == 0){
cout<<""<<endl;
}else{
}
}
cout<<""<<endl;
cout<<"Would you like to re print the results?"<<endl;
cout<<""<<endl;
cout<<"Hit 1 for yes, and 0 for no"<<endl;
cin>>ifstatement;
if(ifstatement == 1){
flag = true;
}else{
flag = false;
}
if(flag == true){
cout<<""<<endl;
cout<<"Print Preorder"<<endl;
genesistree.printpreorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Print in order"<<endl;
genesistree.printinorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Print Postorder"<<endl;
genesistree.printpostorder();
cout<<""<<endl;
cout<<""<<endl;
}else{
if(flag == false){
cout<<""<<endl;
}
}
cout<<""<<endl;
cout<<"Enter the ammount of datavalues you would like to add"<<endl;
cin>>addvalues;
cout<<""<<endl;
if(addvalues > 0){
for(c = deletevalues, c >= 0; c--;){
cout<<"Enter a datavalue to add in the tree"<<endl;
cin>>newnewdata;
genesistree.insertdata(newnewdata);
cout<<""<<endl;
}
}else{
if(deletevalues == 0){
cout<<""<<endl;
}else{
}
}
cout<<""<<endl;
cout<<"Would you like to re print the results?"<<endl;
cout<<""<<endl;
cout<<"Hit 1 for yes, and 0 for no"<<endl;
cin>>ifstatement;
if(ifstatement == 1){
flag = true;
}else{
flag = false;
}
if(flag == true){
cout<<""<<endl;
cout<<"Print Preorder"<<endl;
genesistree.printpreorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Print in order"<<endl;
genesistree.printinorder();
cout<<""<<endl;
cout<<""<<endl;
cout<<"Print Postorder"<<endl;
genesistree.printpostorder();
cout<<""<<endl;
cout<<""<<endl;
}else{
if(flag == false){
cout<<""<<endl;
}
}
*/
cout<<""<<endl;
countNodes(genesistree);
/*
btree<int> mytree;
string QandA[7];
int Tpos[7];
QandA[0] = "Question 1";
QandA[1] = "Question 2";//Y to 0
QandA[2] = "Question 3";//N to 0
QandA[3] = "answer 1";//Y to 1
QandA[4] = "answer 2";//N to 1
QandA[5] = "answer 3";//N to 2
QandA[6] = "answer ";//Y to 2
Tpos[0] = 50;
Tpos[1] = 40;
Tpos[2] = 60;
Tpos[3] = 20;
Tpos[4] = 45;
Tpos[5] = 70;
Tpos[6] = 55;
for(int i = 0; i<=6; i++){
mytree.insertdata2(Tpos[i],QandA[i]);
}
mytree.yesno();
cout<<endl;
*/
return 0;
}
答案 0 :(得分：1)
您的countNodes方法需要treeNode指针。看起来没有任何方法可以访问您的根节点，因此该方法在btree类之外无用。
我会制作另一种方法
template<class datatype>
int btree<datatype>::getNodeCount() const
{
if ( root == NULL ) return 0;
// Otherwise continue counting from root.
...
答案 1 :(得分：0)
以下是解决此问题的一种方法：
在课堂上，一个新功能：
template<class datatype>
class btree{
public:
...
int countNodes();
int countNodes(treenode<datatype> *p);
};
int countNodes（），从程序中调用。
template<class datatype>
int btree<datatype>::countNodes(){
return countNodes(root);
}
int countNodes（treenode * p），在内部调用（可能应该是私有的，因为客户端无论如何都无法访问根节点）：
template<class datatype>
int btree<datatype>::countNodes(treenode<datatype> *p){
int count = 1;
if ( p == NULL ){
return 0;
}else{
count += countNodes(p->lchild);
count += countNodes(p->rchild);
}
return count;
}
请注意，countNodes（treenode * p）的实现也已更改。
然后在主要：
btree<int> genesistree;
genesistree.insertdata(14);
genesistree.insertdata(2);
genesistree.insertdata(34);
genesistree.insertdata(41);
genesistree.insertdata(12);
cout << genesistree.countNodes();
打印5，树的大小。