run c program - stdio.h where do i get it? - c

Question

Looking into learning C. As I understand it when I say #include <stdio.h> it grabs stdio.h from the default location...usually a directory inside your working directory called include. How do I actually get the file stdio.h? Do I need to download a bunch of .h files and move them from project to project inside the include directory? I did the following in a test.c file. I then ran make test and it outputted a binary. When I ran ./test I did not see hello print onto my screen. I thought I wasn't seeing output maybe because it doesn't find the stdio.h library. But then again if I remove the greater than or less than signs in stdio the compiler gives me an error. Any ideas?
I'm on a Mac running this from the command line. I am using: GNU Make 3.81. This program built for i386-apple-darwin10.0
#include <stdio.h>
main()
{
printf("hello");
}
Edit: I have updated my code to include a datatype for the main function and to return 0. I still get the same result...compiles without error and when I run the file ./test it doesn't print anything on screen.
#include <stdio.h>
int main()
{
printf("hello");
return 0;
}
Update:
If I add a \n inside of the printf it works! so this will work:
#include <stdio.h>
int main()
{
printf("hello\n");
return 0;
}

Answer 1

Your code should have preferably
printf("hello\n");
or
puts("hello");
If you want to know where does the standard header file <stdio.h> comes from, you could run your compiler with appropriate flags. If it is gcc, try compiling with
gcc -H -v -Wall hello.c -o hello
Pedantically, a standard header file is even not required to exist as a file; the standard permits an implementation which would process the #include <stdio.h> without accessing the file system (but e.g. by retrieving internal resources inside the compiler, or from a database...). Few compilers behave that way, most really access something in the file system.

Answer 2

If you didn't have the file, you'd get a compilation error.
My guess is the text was printed, but the console closed before you got the chance to see it.
Also, main returns an int, and you should return 0; to signal successful completion.

Answer 3

#include <header.h>, with angle brackets, searches in standard system locations, known to the compiler-- not in your project's subdirectories. In Unix systems (including your Mac, I believe), stdio.h is typically in /usr/include. If you use #include "header.h", you're searching subdirectories first and then the same places as with <header.h>.
But you don't need to find or copy the header to run your program. It is read at compilation time, so your ./test doesn't need it at all. Your program looks like it should have worked. Is it possible that you just typed "test", not "./test", and got the system command "test"? (Suggestion: Don't name your programs "test".)

Answer 4

Just going to leave this here : STILL! in 2018, December... Linux Mint 18.3
has no support for C development.
innocent / # cc ThoseSorts.c
ThoseSorts.c:1:19: fatal error: stdio.h: No such file or directory
compilation terminated.
innocent / # gcc ThoseSorts.c
ThoseSorts.c:1:19: fatal error: stdio.h: No such file or directory
compilation terminated.
innocent / # apt show libc6
(Abbreviated)::
Package: libc6
Version: 2.23-0ubuntu10
Priority: required
Section: libs
Source: glibc
Origin: Ubuntu
Installed-Size: 11.2 MB
Depends: libgcc1
Homepage: http://www.gnu.org/software/libc/libc.html
Description: GNU C Library: Shared libraries
Contains the standard libraries that are used by nearly all programs on
the system. This package includes shared versions of the standard C library
and the standard math library, as well as many others.
innocent / # apt-get install libc6-dev libc-dev
So, magic... and a minute later they are all installed on the
computer and then things work as they should.
Not all distros bundle up all the C support libs in each ISO.
Hunh.
hardlyinnocent / # gcc ThoseSorts.c
hardlyinnocent / # ./a.out
20
18
17
16
... ... ...