Binary tree operations using cpp program

Program illustrates the implementation of various operations on a binary tree implemented using an array

#include<iostream.h>

#include<conio.h>

#include<math.h>

#include<stdlib.h>

const int MAX=100;

class SeqTree

{ private:

          char *tree;

 public:

          SeqTree(void);

          int IsNull(void);

          void create(char,char,char);

          void preorder(int);

          void inorder(int);

          void postorder(int);

          void levelorder(void);

          int height(void);

          int nodes(void);

};

SeqTree::SeqTree()

{        tree=new char[MAX];

          for(int i=0;i<MAX;i++)

                   tree[i]=NULL;

}

int SeqTree::IsNull(void)

{        if(tree[0]==NULL)

                   return 1;

          else

                   return 0;

}

void SeqTree::create(char ele,char par,char lr)

{        int flag=0;

          if(this->IsNull())

          {        tree[0]=ele;

                    return;

          }

          for(int i=0;i<MAX;i++)

                    if(par==tree[i])

                   {        flag=1;

                             if((lr=='l')||(lr=='L'))

                             {        if((2*i+1)>MAX-1)

{        cout<<endl<<"ArrayOverflow. Can't add the node"<<endl;

                                                return;

                                      }

                             if(tree[2*i+1]!=NULL)

{        cout<<"The node "<<par<<" already has a left child. Insertion of"  <<ele<<" is aborted";

                                       return;

                             }

                             tree[2*i+1]=ele;

                   }

                   else

                   {        if((2*i+2)>MAX-1)

{        cout<<endl<<"Array Overflow. Can't add the node"<<endl;

                                       return;

                             }

                    if(tree[2*i+2]!=NULL)

{       cout<<"The node "<<par  <<" already has a right child. Insertion of"  <<ele<<" is aborted";

                             return;

                    }

                    tree[2*i+2]=ele;

                   }

          }

          if(!flag)

          cout<<endl<<"The parent node"<<par<<" is not found in the tree"<<endl;

return;

}

void SeqTree::preorder(int i)

{        if((tree[i]!=NULL)&&(i<MAX))

          {        cout<<tree[i]<<" ";

                   preorder(2*i+1);

                   preorder(2*i+2);

          }                          

          return;

}

void SeqTree::inorder(int i)

{        if((tree[i]!=NULL)&&(i<MAX))

          {        inorder(2*i+1);

                   cout<<tree[i]<<" ";

                   inorder(2*i+2);

          }

          return;

}

void SeqTree::postorder(int i)

{        if((tree[i]!=NULL)&&(i<MAX))

{        postorder(2*i+1);

                   postorder(2*i+2);

                   cout<<tree[i]<<" ";

          }

          return;

}

void SeqTree::levelorder(void)

{        for(int i=0;i<MAX;i++)

          if(tree[i]!=NULL)

                   cout<<tree[i]<<" ";

          return;

}

int SeqTree::nodes(void)

{        int count=0;

          for(int i=0;i<MAX;i++)

                   if(tree[i]!=NULL)count++;

          return count;

}

int SeqTree::height(void)

{        int height=0;

          for(int i=0;i<MAX;i++)

                   if(tree[i]!=NULL)height=i+1;

          return(int(log10(height)/log10(2)));

}

void main()

{        int c;

          SeqTree t;

          while(1)

          {        clrscr();

                   cout<<"\nPerform the Following Operations on a Tree Data Structure";

                   cout<<"\n---------------------------------------------------------"<<endl;

                   cout<<"\n1.Input nodes to Tree";

                   cout<<"\n2.Preorder Traversal";

                   cout<<"\n3.Inorder Traversal";

                   cout<<"\n4.Postorder Traversal";

                   cout<<"\n5.Levelorder Traversal";

                   cout<<"\n6.Height of Tree";

                   cout<<"\n7.Nodes in the Tree";

                   cout<<"\n8.Exit from Program";

                   do

                   {        cout<<"\n\nSelect your Choice(1:8):";

                             cin>>c;

                             cout<<" ";

                   }

                   while((c<1)||(c>8));

          if(c==8)exit(1);

          clrscr();

          switch(c)

          { case 1:

                   clrscr();

                   char element;

                   char parent=NULL;

                   char lr=NULL,rep;

                    do

                   {        cout<<"\nEnter the element to insert:";

                             cin>>element;

                             if(t.IsNull())

cout<<endl<<element<<" is the parent node"<<endl;

                             else

                                      {        cout<<"Enter the parent of "<<element<<" in the tree: \n";

                                      cin>>parent;

                                      do

{        cout<<"Insert as Left child or Right child(L/R):";

                                                cin>>lr;

                                                if((lr!='l')&&(lr!='L')&&(lr!='r')&&(lr!='R'))

                                                cout<<"Invalid Data.Please re-enter"<<endl;

                                      }

                                      while((lr!='l')&&(lr!='L')&&(lr!='r')&&(lr!='R'));

                             }

                             t.create(element,parent,lr);

                    cout<<endl<<"\nAdd More(Y/N):";

                   cin>>rep;

                   }

                   while((rep=='y')||(rep=='Y'));

                   break;

      case 2:

                   clrscr();

                   cout<<"The result of preorder traversal is"<<endl;

                   t.preorder(0);

                   break;

      case 3:

                   clrscr();

                   cout<<"The result of inorder traversal is  "<<endl;

                   t.inorder(0);

                   break;

      case 4:

                   clrscr();

                   cout<<"The result of postorder traversal is"<<endl;

                   t.postorder(0);

                   break;

      case 5:

                   clrscr();

                   cout<<"The result of levelorder traversal is"<<endl;

                   t.levelorder();

                   break;

      case 6:

                   clrscr();

                   cout<<"The Height of the tree is"<<t.height();

                   t.height();

                   break;

      case 7:

                   clrscr();

                   cout<<"The number of elements in the tree is"<<t.nodes();

                   t.nodes();

                   break;

          }

          cout<<endl<<"Press Any Key to Continue...";

          getch();

    }

}