char arrays in C

So, I'm trying to learn C, and currently I'm testing out characters and character arrays. I've put together this code:


#include <stdio.h>
int main()
{
    char hello[7];
    int a, b;
   
    puts("Enter to start:\n");
    getchar();
    fflush(stdin);
   
    puts("Intiated:");

    for(a = 0; a <= 7; ++a){
          hello[a] = getchar();
      }
      fflush(stdin);
     
      for(a = 0; a <= 7; ++a){
            putchar(hello[a]);
            }
           
            fflush(stdin);
            getchar();
            return(0);
}

And it works well (or as well as it is suppose to), but if I change the char array hello's size to something smaller than 7, or change the 7 in both the 'for' parts, than I'll capture more than the number the char array was set to.

So, for example:


#include <stdio.h>
int main()
{
    char hello[3];
    int a, b;
   
    puts("Enter to start:\n");
    getchar();
    fflush(stdin);
   
    puts("Intiated:");

    for(a = 0; a <= 9; ++a){
          hello[a] = getchar();
      }
      fflush(stdin);
     
      for(a = 0; a <= 9; ++a){
            putchar(hello[a]);
            }
           
            fflush(stdin);
            getchar();
            return(0);
}

This will capture 9 characters, even though 'hello' is set to 3. Frankly, I don't mind this. It's better than an overflow or some other error. But what exactly happens? Does it just change the amount of characters the array can hold?

Discarding the return value of getchar.
Not comparing the return value of getchar with EOF and handling the case usefully.
Passing an input stream to fflush.

You are a bad man.