C二叉树前序遍历中序遍历后续遍历递归非递归

///////////////////////
//bt.h
///////////////////////

#include <stdio.h>
#include "stack.h"

#ifndef _BT_H_
#define _BT_H_

typedef struct node{
	struct node *left, *right;
	int value;
}NODE, *P_NODE;

P_NODE initNode(P_NODE target);
void printNode(P_NODE target);
P_NODE init();
P_NODE addLeft(P_NODE target);
P_NODE addRight(P_NODE target);
void pre_re(P_NODE current);
void in_re(P_NODE current);
void post_re(P_NODE current);
void pre(P_NODE current);
void pre_f(P_NODE current);
void pre_lr(P_NODE current);

#endif

///////////////////////
//bt.c
///////////////////////

#include <stdio.h>
#include "stack.h"
#include "bt.h"

P_NODE root;

P_NODE initNode(P_NODE target){
	target -> left = NULL;
	target -> right = NULL;
	target -> value = 0;

	return target;
}

void printNode(P_NODE target){
	printf("%p,%p,%d\n",target -> left, target -> right, target -> value);
}

P_NODE init(){
	root = ((P_NODE)malloc(sizeof(NODE)));
	//printNode(root);
	initNode(root);
	//printNode(root);
	
	return root;
}

P_NODE addLeft(P_NODE target){
	return initNode(target -> left = ((P_NODE)malloc(sizeof(NODE))));
}

P_NODE addRight(P_NODE target){
    return initNode(target -> right = ((P_NODE)malloc(sizeof(NODE))));
}
	
void pre_re(P_NODE current){
	if(current == NULL){
		return;
	}
	printf("%d ", current -> value);
	pre_re(current -> left);
	pre_re(current -> right);
}

void in_re(P_NODE current){
	if(current == NULL){
		return;
	}
	in_re(current -> left); 
	printf("%d ", current -> value);
	in_re(current -> right);
}

void post_re(P_NODE current){
	if(current == NULL){
		return;
	}
	post_re(current -> left);
	post_re(current -> right);
	printf("%d ", current -> value);
}

void pre(P_NODE current){
	clear();
	while(current != NULL || getPos() != -1){
		if(current != NULL){
			printf("%d ", current -> value);
			push(current);
			current = current -> left;
		}else{
			current = ((P_NODE)pop()) -> right;
		}	
	}
	clear();
}

void pre_f(P_NODE current){
	if(current == NULL){
		return;
	}
	clear();
	push(current);
	while(getPos() != -1){
		printf("%d ", current -> value);
		if(current -> right != NULL){
			push(current -> right);
		}
		if(current -> left != NULL){
			current = current -> left;
		}else{
			current = (P_NODE)pop();
		}
	}
	clear();
}

void pre_lr(P_NODE current){
	if(current == NULL){
		return;
	}
	clear();
	push(current);
	while(getPos() != -1){
		current = (P_NODE)pop();
		printf("%d ", current -> value);
		if(current -> right != NULL){
			push(current -> right);
		}
		if(current -> left != NULL){
			push(current -> left);
		}
	}
	clear();
}

///////////////////////
//cc.c
///////////////////////

#include <stdio.h>
#include "bt.h"

extern P_NODE root;

int main(){

	init();

	P_NODE n1, n2, n3, n4, n5, n6;
	n1 = root;
	n1 -> value = 1;
	n2 = addLeft(n1);
	n2 -> value = 2;
	n3 = addRight(n1);
	n3 -> value = 3;
	n4 = addLeft(n2);
	n4 -> value = 4;
	n5 = addRight(n2);
	n5 -> value = 5;
	n6 = addRight(n3);
	n6 -> value = 6;

	int n = 6;

	void (*visitors[])(P_NODE current) = {pre_re, in_re, post_re, pre, pre_f, pre_lr};	
	
	int i;
	for(i = 0; i < n; i++){
		(visitors[i])(root);
		printf("\n");
	}

	return 0;

}