Counting Nodes in a Binary Tree
Question
There is a link to the code above. The point is to make a method to count the nodes in a binary tree, then create two methods that also count the nodes, one for each side of the tree. My question is how to call the method to count the nodes.
My question is how do I call my countNodes method. I don't know what kind of argument it's looking for.
#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;
}
2 answers
solution1
1 2014-05-07 00:44:00
Your countNodes method takes a treeNode pointer. It doesn't look like there is any way to access your root node, so that method is useless outside the btree class.
I would make another method like so
template<class datatype>
int btree<datatype>::getNodeCount() const
{
if ( root == NULL ) return 0;
// Otherwise continue counting from root.
...
solution2
0 2014-05-07 00:45:11
Here's one way of solving this:
In the class, a new function:
template<class datatype>
class btree{
public:
...
int countNodes();
int countNodes(treenode<datatype> *p);
};
int countNodes(), to be called from your program.
template<class datatype>
int btree<datatype>::countNodes(){
return countNodes(root);
}
int countNodes(treenode *p), to be called internally (probably should be private, since clients don't have access to the root node anyways):
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;
}
Note that the implementation for countNodes(treenode *p) has also changed.
Then in main:
btree<int> genesistree;
genesistree.insertdata(14);
genesistree.insertdata(2);
genesistree.insertdata(34);
genesistree.insertdata(41);
genesistree.insertdata(12);
cout << genesistree.countNodes();
Prints 5, the size of the tree.
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