Very basic example code of “The C Programming Language” doesn't work like expected?

Question

I'm a middle experienced Java developer and have many problems learning the C language for my computer science study. I try it with the book "The C Programming Language" which many people seem to recommend.

But I've got problems with the simplest stuff like the EOF in combination with getchar(). Here's the code:

#include<stdio.h>
main()
{
    int i = 0;
    while (getchar() != EOF)
    {
        ++i;
        printf("Count of characters is %d", i);
    }
}

I'm working with Mac OS X Lion and use the "cc" command with "./a.out" for running in terminal, like described in the book to run the file. And what I get is:

• Always counting one character too much
• the while loop never ends! it just waits for another input after reaching end of input ...

I really have no idea what could be the issue. Can someone help?

Answer 1

Always counting one character too much

That could be the newline (enter / return).

the while loop never ends! it just waits for another input after reaching end of input

You are likely not signaling end of input. You should be using CTRL-D to do so.

Answer 2

When you type a character, such as "6" and you click enter (which is equal to \n), then the command "6\n" is sent, so it is 2 characters. If you just press enter, then 'i' will be increased by 1.

The EOF means end of file and its equivalent to ctrld+D. It is useful if you read a text file. Else it is the same as saying "Forever".