Why is getchar() not working for me?

Question

I've just started programming c and I'm working through The C Programming Language by Brian W.Kernighan and Dennis M.Richie.

One of the first examples is character counting and the following program is given, but when I enter a string no result it printed.

#include <stdio.h>

main()
{
   long nc;

   nc = 0;
   while (getchar() != EOF)
          ++nc; 
   printf("%ld\n",nc);
 }

Why isn't this working?

Answer 1

You have to finish the input. Your program will count characters until EOF is encountered. EOF, in the keyboard, can be sent by pressing Ctrl-Z then ENTER if you are in Windows, or Ctrl-D then ENTER if you are in Linux/OS X.

Answer 2

as an addition to the answers that were mentioned , here's how to make your program show results when pressing Enter

 #include <stdio.h>

main()
{
   long nc;

   nc = 0;
   while (getchar() != '\n')
          ++nc; 
   printf("%ld\n",nc);
 }

Answer 3

getchar() is buffered input. Since it is buffered, The control will wait until you press Enter key from the keyboard. In your program, you are checking for EOF by doing

while (getchar() != EOF)

On windows, if you want EOF, you have to input a combination of 2 keys. i.e Ctrl+Z. If you are on LINUX, then EOF is combination of 2 keys Ctrl+D

As said earlier, control will wait at console until you press Enter, so you have to press

• Ctrl+Z Enter - on windows.
• Ctrl+D Enter - on LINUX.

Answer 4

You have to send EOF to program by pressing CTRL+D (for linux) or CTRL+Z (for Windows) to end the while loop.