统计一个字符串中出现的字符及其次数

/*exp10-5.cpp*/

#include <stdio.h>

#include <string.h>

#include <malloc.h>

#define MAXWORD 100

typedef struct tnode

{

char ch;/*字符*/

int count;/*出现次数*/

struct tnode *lchild,*rchild;

}BTree;

void CreaTree(BTree * &p,char c)/*采用递归方式构造一棵二叉排序树*/

{

if(p==NULL)/*p为NULL,则建立一个新结点*/

{

p=(BTree *)malloc(sizeof(BTree));

p->ch=c;

p->count=1;

p->lchild=p->rchild=NULL;

}

else if(c==p->ch)

p->count++;

else if(c<p->ch)

CreaTree(p->lchild,c);

else

CreaTree(p->rchild,c);

}

void InOrder(BTree *p)/*中序遍历BST*/

{

if(p!=NULL)

{

InOrder(p->lchild);/*中序遍历左子树*/

printf("%c(%d)\n",p->ch,p->count);/*访问根结点*/

InOrder(p->rchild);/*中序遍历右子树*/

}

}

void main()

{

BTree *root=NULL;

int i=0;

char str[MAXWORD];

printf("\n");

printf("输入字符串：");

gets(str);

while(str[i]!='\0')

{

CreaTree(root,str[i]);

i++;

}

printf("字符及出现次数：\n");

InOrder(root);

printf("\n");

}