While loop bugs in C

Question

I'm reading the book and I followed the small program in the book, there is a small counting program in which I can't have results.

#include <stdio.h>    

int main() {

    long nc;

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

When I run this and type in some characters, there is no result, and the program is still executing, I can type in characters but still no result. Are there anything wrong in the code?

And I'm running it in Xcode.

How do you tell the program that there is no more data? You should type Control-D on Unix-like systems, or Control-Z on Windows, at the start of a line to indicate there is no more data. Or, if you have a file such as `charcount.c` and your program is `charcount`, you could use `charcount < charcount.c` and you should see the correct answer. — Jonathan Leffler, Aug 16 '16 at 02:27
If you had formatted the code properly, you wouldn't have to ask. — too honest for this site, Aug 16 '16 at 02:28
@Barmar Declareing functions to use directly is OK, but using `#include ` is better. Doing no declaretion is bad. — MikeCAT, Aug 16 '16 at 02:29
@MikeCAT I know, that's why I asked if he's using the header. — Barmar, Aug 16 '16 at 02:31
If you ever find yourself thinking *"Is there a bug in this standard part of C?"*, chances are, the bug *isn't* with C... — David C. Rankin, Aug 16 '16 at 06:03

Derick Alangi · Answer 1 · 2016-08-16T02:43:02.737

1

First of all, if in case you forgot, you need to include the stdio.h header file and secondly, there is nothing wrong with the codes.

while(getchar() != EOF)
    ++nc

The lines of code above checks for end of file and if it returns false, it increments nc and its only when the while loop encounters an end of file before it prints nc. End of file in linux is Ctrl+D and so after inputting your characters, type Ctrl+D and you will have your count since thats the end of file or say input.

edited Aug 16 '16 at 02:43

answered Aug 16 '16 at 02:31

Derick Alangi

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You can also use Ctrl+Z as end of file (EOF) for windows. – Derick Alangi Aug 16 '16 at 02:45
The program needs stdio.h in order to print nc, in case someone is asking why stdio.h – Derick Alangi Aug 16 '16 at 11:01

score 1 · Accepted Answer · edited May 23 '17 at 12:00

1

The code is fine, if you have the required header files included:

#include <stdio.h>

To exit the while loop, you should send a 'EOF' to the program.

There's a case you can reference What is EOF in the C programming language?.

On Linux systems and OS X, the character to input to cause an EOF is Ctrl-D. For Windows, it's Ctrl-Z.

edited May 23 '17 at 12:00

Community

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answered Aug 16 '16 at 02:37

CWLiu

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What is the code using from ``? – Jonathan Leffler Aug 16 '16 at 03:47
Yes, you're right. is not a required header file for this case. – CWLiu Aug 16 '16 at 05:58

While loop bugs in C

2 Answers2