【二叉树】数据结构实验之二叉树的建立与遍历 2136

写这篇主要因为这题概括了我现在学到的二叉树的大部分知识点，所以每一个都用函数标识了。

题目：数据结构实验之二叉树的建立与遍历

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define max(a, b) ((a > b) ? (a) : (b))
char a[55];
int i;
struct tree
{
    int data;
    struct tree *ltree, *rtree;//建立左子树和右子树，这个完全看个人喜好。男左女右都可以
};

struct tree *creat()//建树
{
    struct tree *root;
    if(a[i] == ',')
    {
        i++;
        return NULL;
    }
    else
    {
        root = (struct tree *)malloc(sizeof(struct tree));
        root->data = a[i++];
        root->ltree = creat();
        root->rtree = creat();
    }
    return root;
}

void print_mid(struct tree *root)//中序输出
{
    if(root == NULL)
        return;
    else
    {
        print_mid(root->ltree);
        printf("%c", root->data);
        print_mid(root->rtree);
    }
}

void print_later(struct tree *root)//后序输出
{
    if(root == NULL)
        return;
    else
    {
        print_later(root->ltree);
        print_later(root->rtree);
        printf("%c", root->data);
    }
}

int leaves(struct tree *root)//数叶子数
{
    if(root == NULL)
        return 0;
    else if(root->ltree == NULL && root->rtree == NULL)
        return 1;
    else
        return leaves(root->ltree) + leaves(root->rtree);
}

int depth_tree(struct tree *root)//计算树的深度
{
    int depth = 0;
    if(root)
    {
        int ldepth = depth_tree(root->ltree);
        int rdepth = depth_tree(root->rtree);
        depth = max(ldepth+1, rdepth+1);
    }
    return depth;
}


void print_Sequence(struct tree *root)//树的层序遍历
{
    struct tree *flag[55];
    int head = 0, tail = 0;
    flag[tail++] = root;
    while(head < tail)
    {
        if(flag[head])
        {
            printf("%c", flag[head]->data);
            flag[tail++] = flag[head]->ltree;
            flag[tail++] = flag[head]->rtree;
        }
        head++;
    }
}

int main()
{
    scanf("%s", a);
    i = 0;
    struct tree *root;
    root = (struct tree *)malloc(sizeof(struct tree));
    root = creat();
    print_mid(root);//中序输出
    printf("
");
    print_later(root);//后序输出
    printf("
");
    print_Sequence(root);//树的层序遍历
    printf("%d
", leaves(root));//叶子的数量
    printf("%d
", depth_tree(root));//树的深度
    return 0;
}