inline declarations in Visual Studio 2010

[dvirf]

Whenever I run my code under the Eclipse IDE it first requires me to enter the input, and only then shows the output (Although when I run it through cmd it works fine).
For example: for this code:

#include <stdio.h>

int main()
{
	printf("Hello World!\nEnter a number: ");
	int x = 0;
	scanf("%d",&x);
	printf("You've entered %d", x);
	return 0;
}

I see an empty console every time i run it, and only after I enter a number (let's say 99), I see:

99 //that's actually part of the standard input, and not part of the standard output
Hello World!
Enter a number: You've entered 99

whether the expected result should be

Hello World!
Enter a number:

and only after I enter 99, i would see:

99 //again - this is not the issue here, but just so you won't get confused: this is supposed to be my input
You've entered 99

Old post was:
Title: inline declarations in Visual Studio 2010
Content:
hi,
I usually don't use visual studio for programming in c, but I've decided to try it.
I've noticed that for some reason i can't use inline declaration in Visual studio (although as far as I know it is perfectly legal in c99). For example, when writing this simple program:

#include <stdio.h>

int main()
{	
	printf("Enter an integer: ");
	int x = 0;
	scanf("%d", &x);
	printf("you've entered: %d", x);
	return 0;
}

I get

error C2143: syntax error : missing ';' before type

and

error C2065: 'x' : undeclared identifier

Of course, switching the first two lines in the main function solves this problem.

Since I find Eclipse inconvenient (please excuse me dear Eclipse fans), and I'm used to using VS for programming .Net applications, I'd rather keep using it.

How can I enable inline declaration in Visual Studio 2010?
Thanks in advance!

[CommonTater]

The microsoft compiler is not entirely C-99 compatible... a compromise because both C and C++ code is run through the same compiler.

That however should not be a problem for any reasonable programmer... just adapt and carry on.

[dvirf]

I am not allowed to adapt to it - the university demands us to work by the c99 standard
I switched to Eclipse and I have a question about it. Whenever I run the code under the Eclipse IDE it first requires me to enter the input, and only then shows the output (Although when I run it through cmd it works fine).
For example: for this code:

#include <stdio.h>

int main()
{
	printf("Hello World!\nEnter a number: ");
	int x = 0;
	scanf("%d",&x);
	printf("You've entered %d", x);
	return 0;
}

I see an empty console every time i run it, and only after I enter a number (let's say 99), I see:

99 //that's actually part of the standard input, and not part of the standard output
Hello World!
Enter a number: You've entered 99

whether the expected result should be

Hello World!
Enter a number:

and only after I enter 99, i would see:

99 //again - this is not the issue here, but just so you won't get confused: this is supposed to be my input
You've entered 99

[Bayint Naung]

fflush(stdout). by yourself then or read the link... =)
Not sure why eclipse is not flushing stdout.(usually line buffered).
https://bugs.eclipse.org/bugs/show_bug.cgi?id=173732

[dvirf]

wow thanks!
the

setvbuf(stdout, NULL, _IONBF, 0);

as the first line of the main is a great workaround for this.

two more questions:
1. is there a way to set focus on the console when i press F11 (or run)? because now i have to manually go the the console -> display selected console -> and choose "HelloWorld.exe"
2. can eclipse run the program straight through cmd?

[CommonTater]

I am not allowed to adapt to it - the university demands us to work by the c99 standard

Well if you were on VS... then I assume windows?

The closest to C-99 standards you're going to get is Pelles C. This is a free, standards based compiler and IDE for C-99 coding in CLI and GUI modes on 32 and 64 bit windows. It includes all resource editors, headers and libraries for windows platform development. Be sure to look through the help file, before you start coding... it's the most complete C99 reference I've ever seen. Also there are a number of additional libraries supplied, clearly marked for what is and is not C99...

And yes your code would work on Pelles.

[brewbuck]

wow thanks!
the as the first line of the main is a great workaround for this.

Turning off buffering is a completely ridiculous workaround. The solution is to flush the buffer yourself by calling fflush() when necessary.

[Richardcavell]

I don't disagree with anything that's been said so far, but I think it's worth mentioning that when printf() results in no text being actually printed to screen but rather stored in a buffer, it's usually because there is no newline character at the end of your string. Try this:

printf("You've entered %d\n", x);

Richard

[dvirf]

Well if you were on VS... then I assume windows?

The closest to C-99 standards you're going to get is Pelles C. This is a free, standards based compiler and IDE for C-99 coding in CLI and GUI modes on 32 and 64 bit windows. It includes all resource editors, headers and libraries for windows platform development. Be sure to look through the help file, before you start coding... it's the most complete C99 reference I've ever seen. Also there are a number of additional libraries supplied, clearly marked for what is and is not C99...

And yes your code would work on Pelles.

Thanks for the reply. I wanted to use VS on my laptop, but the university stuff compile our code in unix environment. Apparently they are using Eclipse and want our source code to compile with the following flags for the gcc:

-std=c99 -pedantic-errors -Wall -Werror

Turning off buffering is a completely ridiculous workaround. The solution is to flush the buffer yourself by calling fflush() when necessary.

hmmm.. I can't understand the implications of turning off buffering. Why is it bad?

I don't disagree with anything that's been said so far, but I think it's worth mentioning that when printf() results in no text being actually printed to screen but rather stored in a buffer, it's usually because there is no newline character at the end of your string. Try this:

Code:
printf("You've entered %d\n", x);
Richard

Unfortunately, it doesn't work.

[Elysia]

hmmm.. I can't understand the implications of turning off buffering. Why is it bad?

Because sending text to the screen is a slow process. So what the OS does is that it takes all text that is meant to be sent to the screen and saves it in a so-called buffer. And when it has accumulated enough text or when it decides it is a good time, it flushes the buffer. This basically means it sends the big chunk of text in the buffer to the screen all at once, thereby reducing the latency overhead.

[dvirf]

Elysia, but if i'm using the printf function whenever i want to print, why should the text be buffered?
sorry if i'm a bit naive
i guess that in most of my programs (so far..) i need to send the text to the screen immediately, so i'm having a hard time "accepting" with the above solution being a bad idea.

[Elysia]

What you use doesn't matter. The buffering is there to prevent characters being sent to the screen one-by-one.
It's much faster to take all your characters and send them to the screen at once than to send them individually. Therefore, there is a buffer.

[dvirf]

thank you.