二叉树（C语言）

其中用到了队列 可以用一个循环队列替换 可以翻看之前的博文 ，
这次主要介绍了二叉树的四种遍历以及构建二叉树

#include
#include
#include
using namespace std;
typedef struct Tree
{
    int data;
    struct Tree *lchild;
    struct Tree *rchild;
}Tree;
Tree* CreateTree()
{
    Tree* T;
    T=(Tree*)malloc(sizeof(Tree));
    int data1;
    scanf("%d",&data1);
    if(data1==-1)
    {
        return NULL;
    }
    T->data=data1;
    printf("Please input %d 's Left tree:n",data1);
    T->lchild=CreateTree();
    printf("Please input %d 's Right tree:n",data1);
    T->rchild=CreateTree();
    return T;
}
void FirstPrintTree(Tree *T)
{
    if(T==NULL)
    {
        return ;
    }
    printf("%d ",T->data);
    FirstPrintTree(T->lchild);
    FirstPrintTree(T->rchild);
}
void MidnumPrintTree(Tree *T)
{
    if(T==NULL)
    {
        return ;
    }
    MidnumPrintTree(T->lchild);
    printf("%d ",T->data);
    MidnumPrintTree(T->rchild);
}
void LastPrintTree(Tree *T)
{
    if(T==NULL)
    {
        return ;
    }
    LastPrintTree(T->lchild);
    LastPrintTree(T->rchild);
    printf("%d ",T->data);
}
void LayerOrder(Tree *T)
{
    queueq;
    q.push(T);
    while(!q.empty())
    {
        Tree *flag;
        flag=q.front();
        q.pop();
        printf("%d ",flag->data);
        if(flag->lchild!=NULL)
            q.push(flag->lchild);
        if(flag->rchild!=NULL)
            q.push(flag->rchild);
    }
}
int main()
{
    Tree *T;
    T=CreateTree();
    FirstPrintTree(T);
    printf("n");
    MidnumPrintTree(T);
    printf("n");
    LastPrintTree(T);
    printf("n");
    LayerOrder(T);
    printf("n");
    system("pause");
    return 0;
}