That was exactly my problem! Thanks!
Reversing the string starting with that character would give you your string reversed, but the null terminating zero would be at strrev so when you printed it you wouldn't see anything.
char str, backwards;
printf("Enter a string: ");
fgets(str, sizeof(str), stdin);
for (i = (strlen(str) - 1); i>=0; i--,x++)
backwards[x] = '\0';