输入一个字符串，统计其中单词的个数

#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>

int word_cnt(char *str);
void word_print(char *str, int beg, int end);
//提取单词
void word_split(char *str);

int main()
{
    char str[128];
    //int cnt = 0;
    gets_s(str,128);
    //cnt = word_cnt(str);
    //printf("count = %d
",cnt);
    word_split(str);
    system("pause");
    return 0;
}

int word_cnt(char *str)
{
    int cnt = 0;
    int i = 0;
    while(str[i] != '')
    {
        //根据单词末尾判断
        if(isalnum(str[i]) && (str[i+1] == ' ' || str[i+1] == ''))
            ++cnt;
        //根据单词开头判断
        //if(isalnum(str[i]) && (i == 0 || i != 0 && str[i-1] == ' '))
        ++i;
    }
    return cnt;
}

void word_print(char *str, int beg, int end)
{
    while(beg <= end)
    {
        putchar(str[beg]);
        beg++;
    }
    printf("
");
}

void word_split(char *str)
{
    int cnt = 0;//记录单词的个数
    int i = 0;//下标
    int word_beg, word_end;//一个单词的开始、终止下标

    while(str[i] != '')
    {
        //找到单词的开头
        while(str[i] && !(isalnum(str[i]) && (i== 0 || i != 0 && str[i-1] == ' ')))
            ++i;
        if(str[i] == '')
            break;
        word_beg = i;

        ++cnt;
        //找到单词的结尾
        while(!(isalnum(str[i]) && (str[i+1] == '' || str[i+1] == ' ')))
            ++i;
        word_end = i;
        ++i;
        printf("%dth:  ",cnt);
        word_print(str,word_beg,word_end);
    }
}