字符序列转N叉树

 

//输入如a(b(c,d),e,f(g,h,i))的序列，生成3叉树，并递归打印
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#define N 3
#define BUF_SIZE 1024

char buf[BUF_SIZE], *str = buf;

typedef struct Node
{
    char val;
    struct Node *subTree[N];
}Node, *PNode, *Tree;

Tree MakeTree()
{
    int i;
    PNode pNode = NULL;

    pNode = (PNode)malloc(sizeof(Node));
    assert(pNode != NULL);
    memset(pNode, 0, sizeof(Node));
    pNode->val = *str++;
    if('(' == *str)
    {
        str++;
        i = 0;
        do {
            pNode->subTree[i] = MakeTree();
            if(',' == *str)
                str++;
            else if(')' == *str++)
                break;
            i++;
        } while (i < N);
    }
    return pNode;
}

void WalkTree(Tree tree)
{
    int i;

    if(NULL != tree)
    {
        putchar(tree->val);
        if(tree->subTree[0] == NULL) 
            return;
        putchar('(');
        for(i = 0; i < N; i++)
        {
            WalkTree(tree->subTree[i]);
            if(i + 1 < N && tree->subTree[i + 1] != NULL)
                putchar(',');
        }
        putchar(')');
    }
}

int main()
{
    Tree tree = NULL;
    printf("input str: ");
    while(scanf("%s", buf) != EOF)
    {
        str = buf;
        tree = MakeTree();
        WalkTree(tree);
        printf("\ninput str: ");
    }
    return 0;
}