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

void normalize_path(char *buf) {
    char *wr = buf + 1;
    char *ch = buf + 1;
    while (*ch != '\0') {
        printf("%c", *ch);
        if (*ch == '.' && ch[1] == '/') {
            ch += 2;
            continue;
        }
        if (*ch == '.' && ch[1] == '.' && ch[2] == '/') {
            if (wr > buf + 1) {
                wr -= 2;
            }
            while (wr > buf + 1 && *wr != '/') {
                wr--;
            }
            wr++;
            ch += 3;
            continue;
        }
        while (*ch != '\0' && *ch != '/') {
            *wr = *ch;
            wr++;
            ch++;
        }
        if (ch[1] != '\0') {
            *wr = *ch;
            wr++;
            ch++;
        } else {
            ch++;
        }
    }
    *wr = *ch;
    printf("%s\n", buf);
}

int main(void) {
    char *buf = "/a/b/c/";
    normalize_path(buf);
    buf[6] = 0;
    printf("%s\n", buf);
    return 0;
}