//树的遍历--递归遍历
#include<stdio.h>
#include<stdlib.h>
#include<string.h>typedef struct _TreeNode{//数据域char data;//指针域struct _TreeNode * leftchild;//左孩子指针struct _TreeNode * rightchild;//右孩子指针
}TreeNode, *TreeNodePointer;//先序遍历void PrintRoot(TreeNodePointer root){if (root!=NULL){//访问根节点printf("%c", root->data);//访问左子树PrintRoot(root->leftchild);//访问右子树PrintRoot(root->rightchild);}
}//中序遍历
void PrintRoot2(TreeNodePointer root){if (root != NULL){//访问左子树PrintRoot2(root->leftchild);//访问根节点printf("%c", root->data);//访问右子树PrintRoot2(root->rightchild);}
}//后序遍历
void PrintRoot3(TreeNodePointer root){if (root != NULL){//访问左子树PrintRoot3(root->leftchild);//访问右子树PrintRoot3(root->rightchild);//访问根节点printf("%c", root->data);}
}void Test2(){//定义结构体对象TreeNodePointer t1 = NULL, t2 = NULL, t3 = NULL, t4 = NULL, t5 = NULL;t1 = (TreeNodePointer)malloc(sizeof(TreeNode));if (t1 == NULL){printf("分配内存失败！");goto END;}//初始化数据memset(t1, 0, sizeof(TreeNode));t2 = (TreeNodePointer)malloc(sizeof(TreeNode));if (t2 == NULL){printf("分配内存失败！");goto END;}//初始化数据memset(t2, 0, sizeof(TreeNode));t3 = (TreeNodePointer)malloc(sizeof(TreeNode));if (t3 == NULL){printf("分配内存失败！");goto END;}//初始化数据memset(t3, 0, sizeof(TreeNode));t4 = (TreeNodePointer)malloc(sizeof(TreeNode));if (t4 == NULL){printf("分配内存失败！");goto END;}//初始化数据memset(t4, 0, sizeof(TreeNode));t5 = (TreeNodePointer)malloc(sizeof(TreeNode));if (t5 == NULL){printf("分配内存失败！");goto END;}//初始化数据memset(t5, 0, sizeof(TreeNode));//填充数据域t1->data = 'A';t2->data = 'B';t3->data = 'C';t4->data = 'D';t5->data = 'E';//建立树之间的关系t1->leftchild = t2;t1->rightchild = t3;t2->leftchild = t4;t2->rightchild = NULL;t3->leftchild = t5;t3->rightchild = NULL;// t5是t4的左孩子t4->leftchild = NULL;t4->rightchild = NULL;//t5没有孩子节点t5->leftchild = NULL;t5->rightchild = NULL;//递归遍历树printf("先序遍历\n");PrintRoot(t1);printf("\n");printf("中序遍历\n");PrintRoot2(t1);printf("\n");printf("后序遍历\n");PrintRoot3(t1);END:if (t1 != NULL){free(t1);t1 = NULL;}if (t2 != NULL){free(t2);t2 = NULL;}if (t3 != NULL){free(t3);t3 = NULL;}if (t4 != NULL){free(t4);t4 = NULL;}if (t5 != NULL){free(t5);t5 = NULL;}
}void main(){Test2();printf("\n");system("pause");
}