recurring links

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>

#include <fcntl.h>
#include <string.h>

int main() {
    const char* initialnew = "./polygon/a";
    int lennew = (int) strlen(initialnew);
    char new[lennew + 3];
    new[0] = 0;
    strcat(new, initialnew);

    const char* initialold = "./a";
    int lenold = (int) strlen(initialold);
    char old[lenold + 3];
    old[0] = 0;
    strcat(old, initialold);

    int i = 0;

    while (i < 100) {
        sprintf(old + lenold, "%02d", i);
        sprintf(new + lennew, "%02d", i + 1);
        printf("%s %s\n", old, new);

        if (symlink(old, new) < 0) {
            printf("Error\n");
            exit(-1);
        }

        int fd = open(new, O_RDONLY);
        if (fd < 0)
            break;
        else if (close(fd) < 0) {
            printf("Error2\n");
            exit(-1);
        }

        ++i;
    }

    printf("%d\n", i);

    return 0;
}