数据结构 c代码5：树的建立及三种遍历方式

下面是用c语言实现的一些有关栈的基本操作：

#include<iostream>
using namespace std;
#include <stack>
#define MAXSIZE 1000
typedef int ElemType;

typedef struct TNode
{
    ElemType data;
    struct TNode *lchild, *rchild;
}TNode, *Tree;

/*建立一颗二叉树*/
void BuildTree(Tree &root, int &index)
{    
    index++;
    ElemType temp[] = {2,4,5,-1,3,-1,-1,-1,0,7,6,-1,-1,-1,8,-1,-1};
    if(temp[index]==-1)
    {
        root = NULL;
        return;
    }
    else
    {
        root = (TNode *)malloc(sizeof(TNode));
        root->data = temp[index];
        BuildTree(root->lchild, index);
        BuildTree(root->rchild, index);
    }
}

/*递归先序遍历*/ 
void preOrder(Tree tree)
{
    if(tree == NULL)
    {
        return;
    }
    else
    {
        printf("%d ", tree->data);
        preOrder(tree->lchild);
        preOrder(tree->rchild); 
    }
}

/*递归中序遍历*/ 
void inOrder(Tree tree)
{
    if(tree == NULL)
    {
        return;
    }
    else 
    {
        inOrder(tree->lchild);
        printf("%d ", tree->data);
        inOrder(tree->rchild);
    }
}
/*递归后序遍历*/ 
void postOrder(Tree tree)
{
    if(tree == NULL)
    {
        return ;
    }
    else
    {
        postOrder(tree->lchild);
        postOrder(tree->rchild);
        printf("%d ", tree->data);
    }
}

/*非递归的进行先序遍历*/
void recurrence_preOrder(Tree tree)
{
    stack<Tree> s;
    Tree p =tree;
    while(p||(!s.empty())) 
    {
        if(p)
        {
            cout<<p->data<<" ";
            s.push(p);
            p=p->lchild;
        }
        else
        {
            p=s.top()->rchild;
            s.pop();            
        }
    }
} 

void recurrence_InOrder(Tree tree)
{
    stack<Tree> s;
    TNode *p = tree;
    while(p||!s.empty())
    {
        while(p)
        {
            s.push(p);
            p = p->lchild;
        }
        if(!s.empty())
        {
            p = s.top();
            cout<<p->data<<" ";
            s.pop();
            p = p->rchild;
        }
    } 
    cout<<endl;
} 
int main()
{
    Tree tree;
    int index = -1;
    BuildTree(tree, index);
     cout<<"构建的树："<<endl
        <<"1            2 "<<endl
        <<"2        4       0 "<<endl
        <<"3     5   -1    7  8 "<<endl
        <<"4  -1  3      6 -1 -1 -1 "<<endl
        <<"5    -1 -1  -1 -1 "<<endl<<endl;
        
    /*先序遍历*/
    cout<<"递归先序遍历结果为："<<endl;
    preOrder(tree); 
    
    /*中序遍历*/
    cout<<"\n递归中序遍历结果为："<<endl; 
    inOrder(tree);
    
    /*后续遍历*/
    cout<<"\n递归后续遍历结果为："<<endl;
    postOrder(tree);
    
    /*非递归先序遍历*/ 
    cout<<"\n非递归先序遍历的结果为："<<endl; 
    recurrence_preOrder(tree);
    
    /*非递归中序遍历*/
    cout<<"\n非递归中序遍历的结果为："<<endl;
    recurrence_InOrder(tree); 
    system("pause");
    return 0;
}

其中由于非递归后续遍历比较麻烦，所以这里没有编写代码。
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