二叉树的建立及遍历各种递归

递归简直太难了啊

#include<stdio.h> #include<malloc.h> #define OK 1 #define ERROR 0 #define TRUE 1 #define FLASE 0 #define OVERFLOW 2 typedef int Status; #define TElemType char typedef struct BiTNode{ TElemType data; struct BiTNode * lchild, * rchild; //左右孩子指针 }BiTNode, * BiTree; Status CreateBiTree(BiTree &T) {//先序建立二叉树 char ch; scanf("%c", &ch); if(ch==' ') T=NULL; else { if(!(T=(BiTNode *)malloc(sizeof(BiTNode)))) exit(OVERFLOW); T->data=ch; CreateBiTree(T->lchild); //构造左子树 CreateBiTree(T->rchild); //构造右子树 } return OK; }//CreateBiTree Status PrintElement(TElemType e) { printf("%c ", e); return OK; }//相当于Visit函数 Status PreOrderTraverse(BiTree T, Status(*Visit)(TElemType e)) //先序遍历T的递归算法 { if(T) { if(Visit(T->data)) if(PreOrderTraverse(T->lchild, Visit)) if(PreOrderTraverse(T->rchild, Visit)) return OK; return ERROR; } else return OK; }//PreOrderTraverse Status InOrderTraverse(BiTree T) //中序递归遍历 { if(T) { InOrderTraverse(T->lchild); //最左节点 printf("%c ",T->data); InOrderTraverse(T->rchild); } return OK; } Status PostOrderTraverse(BiTree T) //后续递归遍历 { if(T) { PostOrderTraverse(T->lchild); PostOrderTraverse(T->rchild); printf("%c ",T->data); } return OK; } int LeavesNum(BiTree T) //递归法求叶子个数 { if(T) { if((T->lchild==NULL) && (T->rchild==NULL)) { return 1; } return (LeavesNum(T->lchild)+LeavesNum(T->rchild)); } return 0; } Status Exchange(BiTree T) //递归法交换树的左右子树 { BiTree temp; if(T) { Exchange(T->lchild); Exchange(T->rchild); temp = T->lchild; T->lchild = T->rchild; T->rchild = temp; } return OK; } int Depth(BiTree T) //求树的高度 { int lh,rh; lh = rh = 0; BiTree p = T; if(p==NULL) { return 0; } else { lh = Depth(p->lchild); rh = Depth(p->rchild); return(lh > rh ? (lh+1):(rh+1)); } } int Num_Of_Node(BiTree T) //求树的结点数 { if(T==NULL) return 0 ; else return Num_Of_Node(T->lchild)+Num_Of_Node(T->rchild)+1; } int main() { BiTree T; printf("以先序序列建树：\n"); CreateBiTree(T); printf("原树的前、中、后序遍历如下：\n"); PreOrderTraverse(T, PrintElement); printf("\n"); InOrderTraverse(T); printf("\n"); PostOrderTraverse(T); printf("\n"); int leavesnum; leavesnum = LeavesNum(T); printf("原树的叶子数为： %d\n", leavesnum); int depth; depth = Depth(T); printf("原树的深度值为： %d\n", depth); int num_of_node; num_of_node = Num_Of_Node(T); printf("原树的结点数为： %d\n", num_of_node); Exchange(T); //交换树的左右结点 printf("交换左右结点后的前中后序遍历为：\n"); PreOrderTraverse(T, PrintElement); printf("\n"); InOrderTraverse(T); printf("\n"); PostOrderTraverse(T); printf("\n"); leavesnum = LeavesNum(T); printf("交换后的叶子数为： %d\n", leavesnum); depth = Depth(T); printf("交换后树的深度为： %d\n", depth); num_of_node = Num_Of_Node(T); printf("交换后的结点数为： %d\n", num_of_node); system("pause"); return 0; }