Trying to "copy" one string in reverse - arrays

Question

I've been trying to "copy" one string to another, in reverse.
It kindof works, but it prints some weird symbols.
I've tried setting char copy[length2] but that makes the program not run at all.
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define ARR_SIZE 50
int main()
{
char string[ARR_SIZE];
printf("Enter char array!\n");
fgets(string, ARR_SIZE, stdin);
string[strlen(string) - 1] = '\0';
int length = (strlen(string) - 1);
int length2 = (strlen(string) - 1);
printf("%s\t%d\n", string, length);
for (int i = 0; i <= length; i++)
{
printf("INDEX = %d CHAR = %c\n", i, string[i]);
}
printf("%d", length2);
char copy[ARR_SIZE];
for (int i = 0; i <= length2; i++)
{
copy[i] = string[length];
length--;
}
printf("\n%s", copy);
}

Answer 1

These are the minimal modifications I'd make to your code:
#include <stdio.h>
#include <string.h>
// remove unneeded headers
#define ARR_SIZE 50
int main(void)
{
char string[ARR_SIZE];
printf("Enter char array!\n");
fgets(string, ARR_SIZE, stdin);
string[strlen(string) - 1] = '\0';
// remove the -1 on the string length calculation, the NUL terminator is not
// included in strlen's return value
int length = strlen(string);
// no sense in calling strlen twice
int length2 = length;
// fixed `length` now prints the correct length
printf("%s\t%d\n", string, length);
// change from <= to <. The array indices where the characters live are
// [0, length-1].
for (int i = 0; i < length; i++)
{
printf("INDEX = %d CHAR = %c\n", i, string[i]);
}
// fixed `length2` now prints the correct length
printf("%d", length2);
char copy[ARR_SIZE];
for (int i = 0; i < length2; i++)
{
// last character in `string` lives at the `length`-1 index
copy[i] = string[length-1];
length--;
}
// `length2` is the index after the last char in `copy`, this needs
// to be NUL terminated.
copy[length2] = '\0';
// prints the reversed string
printf("\n%s", copy);
}
Demo

Answer 2

Use functions.
Terminate strings with null character \0 or simply 0.
char *copyreverse(char *dest, const char *src)
{
size_t len = strlen(src);
const char *end = src + len - !!len;
char *wrk = dest;
while(len--)
*wrk++ = *end--;
*wrk = 0;
return dest;
}
int main()
{
char dest[10];
char *src = "hello";
printf("`%s` reversed `%s`\n", src, copyreverse(dest, src));
}