Behavior of getchar() inside while loop

Question

int main()
{
int c;

  while ( (c = getchar())  != EOF)
    putchar(c);

}

Now ,running the above program produces

$./a.out thisisthelinewhosestoragelocationisamysterytome -- LINE1 thisisthelinewhosestoragelocationisamysterytome -- LINE2

When i entered the characters of LINE1 , i think the functions getchar() and putchar() , have been processing the characters , or am i wrong ?

Here is my question.

After i hit enter , my LINE1 is duplicated exactly to LINE2 , which means it should have been buffered elsewhere , so where is it stored ? Also why is it implemented this way ?

Answer 1

Your program doesn't receive input from the shell until you've entered a whole line.

Answer 2

The default behavior of the system is to buffer the input until it sees a newline so that you have the option of hitting backspace and making edits to the line before your program sees it.