simple C program, printf not printing

Question

I'm new here , asking questions at least. Always have been able to find good answers here. Trying to get back into programming and relearning C but ran into weird issue.

#include <stdio.h>

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

When I run it, after I type in any amount of characters and hit enter, it does not print the value of nc. After hitting enter, I can start typing again and well, same story. Really can't see what could be wrong. The only way it works is if I place both ++nc and the printf within brackets. But then when I hit enter, it gives the value 1-to-nc, which is not what I want. I just want nc. Needless to say the type is not the issue either. Thanks in advance

How do I get EOF?, hitting Control and D only gives me ^D. which does nothing — hops1
– hops1, Commented Jun 14, 2013 at 21:33
What OS are you using? Does Control-D after ENTER work as EOF? — Jens
– Jens, Commented Jun 14, 2013 at 21:39
Actually I just found Ctrl-Z seems to work as EOF on my system. I'm running windows 7 — hops1
– hops1, Commented Jun 14, 2013 at 22:00

Jesus Ramos · Accepted Answer · 2013-06-14 21:19:06Z

7

Type Ctrl-D in your terminal to send EOF. You may want

while (getchar() != '\n')

instead if you want it to work with enter.

answered Jun 14, 2013 at 21:19

Jesus Ramos

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3 Comments

Jens Over a year ago

That's an infinite loop if getchar returns EOF.

Jesus Ramos Over a year ago

@Jens I know I was saying if he wanted it to work with pressing the enter key instead of EOF.

Jens Over a year ago

But how hard is it to fix this bug and make the program deal with real world input, which always has an EOF eventually?

jh314 · Accepted Answer · 2013-06-14 21:19:10Z

3

You need to hit Ctrl-D to get a EOF.

answered Jun 14, 2013 at 21:19

jh314

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3 Comments

hops1 Over a year ago

Control d only seems to give me ^D

hops1 Over a year ago

found a different solution, but could you explain the ^D pls thanks

hops1 Over a year ago

I Figured it out, its Ctrl-Z on my system

Ajax · Accepted Answer · 2013-06-15 14:15:18Z

1

try

while(getchar() != '\n') nc++;

Edit : Assuming the input taken from console, '\n' suffices.

edited Jun 15, 2013 at 14:15

answered Jun 14, 2013 at 21:19

Ajax

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3 Comments

Jens Over a year ago

That's an infinite loop if getchar returns EOF.

Ajax Over a year ago

@Jens: as I am taking input manually from console, i can stop the program by hitting enter.

Jens Over a year ago

It's a bug nonetheless. What if someone runs the program with stdin redirected from a file? What if that file is empty?

Gregor Ophey · Accepted Answer · 2013-06-14 21:51:41Z

0

If you just want to get nc printed inside the loop, you should include the print statement in the loop like so:

#include <stdio.h>

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

That prints nc once for each character after hitting [enter], maybe not what you want.

If you want to print nc once per line use scanf and do:

#include <stdio.h>
#include <string.h>

main()
{
    long nc;
    nc = 0;
    char buf[128];
    while (scanf("%s",&buf) > 0) {
      int len = strlen(buf);
      nc += len;
      printf("%ld \n", nc);
    } 
}

answered Jun 14, 2013 at 21:51

Gregor Ophey

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