First... post your code here. Don't make us go chasing it... 'cause we won't.
Buffered input means that every keystroke... even ones that don't get processed, are stored in an input buffer. At some point you need to clear it out.
For example, when you have..
Code:
int c;
printf("Enter a letter : ");
c = getchar();
so the prompt comes up and you press in A then you hit the <enter> key... BOTH keystrokes go into the buffer, the A is read back by the getchar() leaving the <enter> key behind... Now you need to clear that out before calling your next input function, or it will simply see you pressing <enter>.
Worse still you could enter "My name is fred and I like to eat spam" and hit enter... The only thing that is assigned is the M, leaving the rest behind.
The usual method is to loop until you find the newline...
Code:
while(getchar() != '\n');
... is usually adequate to ensure an empty input buffer for your next user input.