要点：二叉树遍历，要针对基本图形的遍历，先序（NLR），中序（LNR），后序（LRN），且往上看，它是某节点的左子，但往下看，它可能还是某节点的根，这时就要继续往下找，直到找到没有子（也就是叶子）时，左子，才是真正的左子，自己体会。
图形：
程序：
#include<stdio.h> #include<stdlib.h> struct node{ char data; struct node* left; struct node* right; }; struct node* newNode(char data){ struct node* node = (struct node*)malloc(sizeof(struct node)); node->data=data; node->left=NULL; node->right=NULL; return node; } void printPostorder(struct node* node){ if(node == NULL) return; printPostorder(node->left); printPostorder(node->right); printf("%c ",node->data); } void printInorder(struct node* node){ if(node==NULL){ return; } printInorder(node->left); printf("%c ",node->data); printInorder(node->right); } void printPreorder(struct node* node){ if(node==NULL){ return; } printf("%c ",node->data); printPreorder(node->left); printPreorder(node->right); } int main(){ struct node *root=newNode(‘A‘); root->left=newNode(‘B‘); root->right=newNode(‘C‘); root->left->left=newNode(‘D‘); root->right->left=newNode(‘F‘); root->right->right=newNode(‘H‘); root->left->left->right=newNode(‘E‘); root->right->right->left=newNode(‘I‘); root->right->right->left->right=newNode(‘G‘); printf("\nPreorder raversal of binary tree is \n"); printPreorder(root); printf("\nInorder raversal of binary tree is \n"); printInorder(root); printf("\nPostorder raversal of binary tree is \n"); printPostorder(root); return 0; }
输出：
Preorder raversal of binary tree is A B D E C F H I G Inorder raversal of binary tree is D E B A F C I G H Postorder raversal of binary tree is E D B F G I H C A
原文：https://www.cnblogs.com/litifeng/p/10662009.html