倒序打印非数字开头的可视字符串

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

#define MAX 65535
// char *fgets(char *buf, int bufsize, FILE *stream)；

void reverseWord(char* b, char* e) {
    while(e-b > 0) {
        char tmp = *b;
        *(b++) = *e;
        *(e--) = tmp;
    }
}

int main() {
    char s[MAX];
    fgets(s, MAX, stdin);
    // char *fgets(char *buf, int bufsize, FILE *stream);
    int slen = strlen(s)-1;
    //including the '\n', so need minus 1

    int splen = 0;
    //as it is
    for(char* ps = s; ps-s < slen; ps++) {
        //get the indexes of blank spaces
        if (*ps == ' ') {
            splen += 1;
        }
    }
    printf("Space counts: %d\n", splen);

    int idx[splen];
    //indexes of blank space
    int* pi = idx;
    for(char* ps = s; ps-s < slen; ps++) {
        if (*ps == ' ') {
            *(pi++) = ps-s;
        }
    }

    char* last = s-1;   //上一个空格
    char* this = s-1;

    for (int* pi = idx; pi-idx < splen; pi++) {
        this = s + *pi;     //当前空格的位置
        if(this > s) {      //第一个字符不是空格
            char* b = last + 1;
            char* e = this - 1;
            if(*b < '0' || *b > '9')
                reverseWord(b, e);
        }
        last = this;    //做记号，上一个空格在哪
        if(pi-idx == splen-1 && this < s+slen-1) {
            this = s + slen;
            char* b = last + 1;
            char* e = this - 1;
            if(*b < '0' || *b > '9')
                reverseWord(b, e);
        }
    }

    fputs(s, stdout);

    return 0;
}