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#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
#define COUNTNODES 5
#define ROOTLEVEL 0
struct Tree{
int num;
Tree *left, *right;
};
void AddNode(int x, Tree *&MyTree);
void Showtree(Tree *&MyTree, int level);
int countLevel(Tree *MyTree, int N);
void DeleteTree(Tree *&MyTree);
int main()
{
Tree *phead = nullptr;
int num;
srand(time(NULL));
for (int i = 0; i < COUNTNODES; i++){
num = rand()%100;
AddNode(num, phead);
}
Showtree(phead, ROOTLEVEL);
int level;
cout << "Input level : ";
cin >> level;
cout << "Number of nodes on level " << level << " = " << countLevel(phead, level) << endl;
DeleteTree(phead);
system("pause");
return 0;
}
void AddNode(int x, Tree *&MyTree)
{
if (MyTree == nullptr){
MyTree = new Tree;
MyTree->num = x;
MyTree->left = MyTree->right = nullptr;
}
else{
if (x < MyTree->num){
if(MyTree->left != nullptr)
AddNode(x, MyTree->left);
else{
MyTree->left = new Tree;
MyTree->left->left = MyTree->left->right = nullptr;
MyTree->left->num = x;
}
}
if (x > MyTree->num){
if (MyTree->right != nullptr)
AddNode(x, MyTree->right);
else{
MyTree->right = new Tree;
MyTree->right->left = MyTree->right->right = nullptr;
MyTree->right->num = x;
}
}
}
}
void Showtree(Tree *&MyTree, int level)
{
if (MyTree){
Showtree(MyTree->left, level + 1);
for (int i = 0; i < level; i++)
cout <<  "    ";
cout << MyTree->num << endl;
Showtree(MyTree->right, level + 1);
}
}
int countLevel(Tree *MyTree, int N)
{
if (MyTree == NULL)
return 0;
if (N == 0)
return 1;
return countLevel(MyTree->left, N - 1) + countLevel(MyTree->right, N - 1);
}
void DeleteTree(Tree *&MyTree)
{
if(MyTree!=nullptr){
DeleteTree(MyTree->left);
DeleteTree(MyTree->right);
delete MyTree;
MyTree = nullptr;
}
}