数据结构关于二叉树的先序遍历中序遍历及后续遍历复习笔记

Posted 2022-11-28 沉默的小宇宙

树的概念就不多说了，直接上最简单的代码，关键的一点需要复习下【递归】的概念。

typedef struct node

	int data;
	struct node *left;
	struct node *right;
NODE_T,*PNODE_T;
/*
先序遍历：根->左->右
*/
void preorder(PNODE_T pNode)

	if(NULL != pNode)
	
		printf(" %d",pNode->data);
		preorder(pNode->left);
		preorder(pNode->right);
	


/*
中序遍历：左->根->右
*/
void inorder(PNODE_T pNode)

	if(NULL != pNode)
	
		inorder(pNode->left);
		printf(" %d",pNode->data);
		inorder(pNode->right);
	


/*
后序遍历：左->右->根
*/
void postorder(PNODE_T pNode)

	if(NULL != pNode)
	
		postorder(pNode->left);
		postorder(pNode->right);
		printf(" %d",pNode->data);
	


void test_binary_tree(void)

	NODE_T n1;
	NODE_T n2;
	NODE_T n3;
	NODE_T n4;
	NODE_T n5;
	NODE_T n6;
	
	debug_set_level ( DBG_LEVEL_ALL );
	
	DEBUG_INFO(" test start!\\n");
	delay_ms(10);
	n1.data = 5;
	n2.data = 6;
	n3.data = 7;
	n4.data = 8;
	n5.data = 9;
	n6.data = 10;
	
	n1.left = &n2;
	n1.right = &n3;

	n2.left = &n4;
	n2.right = &n5;

	n3.left = &n6;
	n3.right = NULL;

	n4.left = NULL;
	n4.right = NULL;
	
	n5.left = NULL;
	n5.right = NULL;
	
	n6.left = NULL;
	n6.right = NULL;
	DEBUG_INFO("preorder test !\\n");delay_ms(10);
	preorder(&n1);	// 5 6 8 9 7 10
	printf("\\n");
	DEBUG_INFO("inorder test !\\n");delay_ms(10);
	inorder(&n1);	// 8 6 9 5 10 7
	printf("\\n");
	DEBUG_INFO("postorder test !\\n");delay_ms(10);
	postorder(&n1);	// 8 9 6 10 7 5
	printf("\\n");
	DEBUG_INFO(" end!\\n");
	
	while(1)
	
		
	

测试数据

 测试结果：

[INFO][bsp_test.c #396][@test_tree]: test start!
[INFO][bsp_test.c #422][@test_tree]:preorder test !
 5 6 8 9 7 10
[INFO][bsp_test.c #425][@test_tree]:inorder test !
 8 6 9 5 10 7
[INFO][bsp_test.c #428][@test_tree]:postorder test !
 8 9 6 10 7 5
[INFO][bsp_test.c #431][@test_tree]: end!

By Urien 2021/11/7