二叉树的实现

1.结点

template <typename T>
class BiNode{
public:
    T data;
    BiNode<T> *lchild,*rchild;
};

2.框架

template <typename T>
class BiTree
{
  public:
       BiTree(){root=new BiNode<T>;root=Creat();}//前序扩展构造
       BiTree(T pre[],T in[],int s){root=new BiNode<T>;root=Creat2(pre,in,s);}//前序加中序构造
       void PreOrder(){PreOrder(root);}
       void InOrder(){InOrder(root);}
       void PostOrder(){PostOrder(root);}

  private:
        BiNode<T> *root;
        BiNode<T> *Creat();
        BiNode<T> *Creat2(T pre[],T in[],int s);
        void PreOrder(BiNode<T> *bt);
        void InOrder(BiNode<T> *bt);
        void PostOrder(BiNode<T> *bt);

 };

3.前序扩展构造

template <typename T>
BiNode<T>* BiTree<T>::Creat(){
    BiNode<T> *bt;
    char ch;
    cin>>ch;
    if(ch=='#') bt=NULL ;
    else{
        bt=new BiNode<T>;
        bt->data=ch;
        bt->lchild=Creat();
        bt->rchild=Creat();
    }
    return bt;
}

4.前序+中序构造

template <typename T>
BiNode<T>* BiTree<T>::Creat2(T pre[],T in[],int s){
    if(s==0) return NULL;
    char v=pre[0];
    int r=-1;
    for(int i=0;i<s;i++)
    if(in[i]==v){
        r=i;
        break;
    }
    BiNode<T> *f=new BiNode<T>;
    f->data=v;
    f->lchild=Creat2(pre+1,in,r);
    f->rchild=Creat2(pre+1+r,in+1+r,s-1-r);
    return f;

}

5.前中后序遍历

template <typename T>
void BiTree<T>::PreOrder(BiNode<T> *bt)
{
    if(bt==nullptr) return;
    else{
        cout<<bt->data<<endl;
        PreOrder(bt->lchild);
        PreOrder(bt->rchild);
    }
}
template <typename T>
void BiTree<T>::InOrder(BiNode<T> *bt)
{
    if(bt==nullptr) return;
    else{
        InOrder(bt->lchild);
        cout<<bt->data<<endl;
        InOrder(bt->rchild);
    }
}
template <typename T>
void BiTree<T>::PostOrder(BiNode<T> *bt)
{
    if(bt==nullptr) return;
    else{
        PostOrder(bt->lchild);
        PostOrder(bt->rchild);
        cout<<bt->data<<endl;
    }
}