二叉樹（先序創建，前中後序及按層遍歷）

.h文件

#include 
#include 

struct biTree{
	char data;
	struct biTree * lchild, * rchild;
};

struct biTree * initBiTree();

struct biTree * createBiTree(struct biTree * bt);

int preOrderTraverse(struct biTree * bt);

int inOrderTraverse(struct biTree * bt);

int postOrderTraverse(struct biTree * bt);

int levelOrderTraverse(struct biTree * bt);

.c文件

#include "二叉樹.h"

#define MAX 100

struct biTree * initBiTree(){
	struct biTree * bt;
	bt=(struct biTree *)malloc(sizeof(struct biTree));
	bt->lchild=NULL;
	bt->rchild=NULL;
	return bt;
}

struct biTree * createBiTree(struct biTree * bt){//先序創建二叉樹
	char ch;
	ch=getchar();
	if(ch=='#'){
		bt=NULL;
	}
	else{
		bt=(struct biTree *)malloc(sizeof(struct biTree));
		bt->data=ch;
		bt->lchild=createBiTree(bt->lchild);
		bt->rchild=createBiTree(bt->rchild);
	}
	return bt;
}

int preOrderTraverse(struct biTree * bt){
	if(bt!=NULL){
		printf("%c ",bt->data);
		preOrderTraverse(bt->lchild);
		preOrderTraverse(bt->rchild);
	}
	return 0;
}

int inOrderTraverse(struct biTree * bt){
	if(bt!=NULL){
		inOrderTraverse(bt->lchild);
		printf("%c ",bt->data);
		inOrderTraverse(bt->rchild);
	}
	return 0;
}

int postOrderTraverse(struct biTree * bt){
	if(bt!=NULL){
		postOrderTraverse(bt->lchild);
		postOrderTraverse(bt->rchild);
		printf("%c ",bt->data);
	}
	return 0;
}

int levelOrderTraverse(struct biTree * bt){
	struct biTree * Queue[MAX],* p;
	int front,rear;
	front=rear=0;
	if(bt!=NULL){
		Queue[rear]=bt;
		rear++;
		while(front!=rear)
		{
			p=Queue[front];
			front++;
			printf("%c ",p->data);
			if(p->lchild!=NULL){
				Queue[rear]=p->lchild;
				rear++;
			}
			if(p->rchild!=NULL){
				Queue[rear]=p->rchild;
				rear++;
			}
		}
	}
	return 0;
}

int main(){
	struct biTree * bt;
	bt=initBiTree();
	bt=createBiTree(bt);
	preOrderTraverse(bt);
	printf("\n");
	inOrderTraverse(bt);
	printf("\n");
	postOrderTraverse(bt);
	printf("\n");
	levelOrderTraverse(bt);
	return 0;
}