#include "stdio.h"
 main()
{
    char c;
    int letters = 0, space = 0, digit = 0, others = 0;
    printf("please input \n");
   
    while ((c = getchar()) != '\n')
    {
        if (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z')
        letters++;
        else if (c == ' ')
        space++;
        else if (c >= '0' && c <= '9')
        digit++;
        else
        others++;
    }
    printf("all in all:letters=%d space=%d digit=%d others=%d", letters, space, digit, others);
}

用的cfree怎么不行啊