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

enum Direction { FORWARD, BACKWARD };

void print_backward_then_forward_1(char* s) {
    int n = strlen(s);

    for(int i = n - 1; i >= 0; i--) {
        fputc(s[i], stdout);
    }

    for(int i = 0; i < n; i++) {
        fputc(s[i], stdout);
    }
    fputc('\n', stdout);
}

void _print_backward_then_forward_helper(char* s, enum Direction direction) {
    int n = strlen(s);
    for(int i = 0; i < n; i++) {
        int str_idx = (direction == FORWARD ? i : n - i - 1);
        fputc(s[str_idx], stdout);
    }
}

void print_backward_then_forward_2(char* s) {
    _print_backward_then_forward_helper(s, false);
    _print_backward_then_forward_helper(s, true);
    fputc('\n', stdout);
}

int main(int argc, char* argv[]) {
    print_backward_then_forward_1("eyeeros");
    printf("------------------\n");
    print_backward_then_forward_2("eyeeros");
    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */