Program doesn't show up

Hi,

I am a beginner in C. Actually I started few days ago.

I have a problem when I compile a program with DJGPP (on WinXP). The program seems to compile fine but when I run it, it does the task it should be doin but it closes immidiately after that and doesn't let me see it.

My first program is like this:

Code:

#include <stdio.h>

main()

{
	printf("This is my first program");
}

I tried to put in the return 0; thing but it doesn't solve the problem. I know some probably laugh when they see that but im a beginner. Help pls.

Read the faq before posting, or atleast do a board search. This is what you are looking for.

Also, it should be int main() not main() and main returns 0 on successful execution of the program, so put a return 0 in the end.

That happens a lot with IDE's. What you need to do is pause the program somehow before it ends and closes the window. The "best" way according to a lot of people is to ask for input before the return:

Code:

#include <stdio.h>

int main()
{
  printf("This is my first program");

  getchar(); /* I pause the program */

  return 0;
}

The only problem with this is if stdin, where getchar gets chars from, isn't empty. In that case, you need to clean it up by reading and discarding characters until there's nothing left:

Code:

#include <stdio.h>

int main()
{
  printf("This is my first program");

  while ( getchar() != '\n' )
    ;
  getchar(); /* I pause the program */

  return 0;
}

Note that I'm keeping it as simple as possible since you're new to the language. I don't want to overwhelm you with the more complicated rock solid way to go about things.

not sure if this only works for windows seeing as it's a system call, but system("PAUSE"); waits for any key to continue,.. try this:

Code:

#include <stdio.h>

/* this is a comment: if you use "int " before the name of a function,
you tell the compiler that this function will return an integer value.
That's why you need the "return 0;" at the end in order for it to
compile. */

int main()
{
  printf("This is my first program");

  system("PAUSE");

  return 0;
}

Code:

#include <stdio.h>

/* if you write "void " before the program name you tell the compiler
that the program won't return a value. Which means you can skip
the "return 0;". Some people here claim that this way of doing it is
unclean though. Either way, you HAVE to write something before
the program name in order for it to compile... */

void main()
{
  printf("This is my first program");

  system("PAUSE");
}

> Some people here claim that this way of doing it is unclean though.
It isn't a claim, it's a simple fact in the ANSI-C standard. In a hosted environment, main returns int - no ifs, buts or maybes about it.

> fflush(stdin); //this cleans out stdin aswell
Rubbish - just read the FAQ will you.

Originally Posted by Salem

> Some people here claim that this way of doing it is unclean though.
It isn't a claim, it's a simple fact in the ANSI-C standard. In a hosted environment, main returns int - no ifs, buts or maybes about it.

yet I've never had a problem compiling with void. Maybe my code's not complex enough,.. and where's this FAQ you keep talking about?..

anyways, the problem with this guys code was that he didn't have anything befor the function name and I just wanted to explain why there need sto be something there with an example as support. I'll make sure I only use "int main" from now on... Now where's this FAQ at?...

FAQ

• FAQ > What's the difference between... > main() / void main() / int main() / int main(void) / int main(int argc, char *argv[])
• FAQ > Explanations of... > Why fflush(stdin) is wrong
• FAQ > How do I... (Level 1) > How do I get my program to wait for a keypress? (already mentioned)
• FAQ > How do I... (Level 1) > Stop my Windows Console from disappearing everytime I run my program?

Thanks all have been very helpful. I searched for this problem but didnt find anything