Confusion in macro

Question

The following code works fine

#define open {
#define close }
#include<stdio.h>
#define int char

 main()
 open
 int a ;
 printf("This is testing code" );
 close

But If I exchange the lines

#include<stdio.h>
#define int char 

as

#define int char 
#include<stdio.h> 

it throws lot of errors like this

In file included from /usr/include/stdio.h:36,
                 from print.c:19:
/usr/include/bits/types.h:35: error: both 'short' and 'char' in declaration specifiers
/usr/include/bits/types.h:37: error: both 'long' and 'char' in declaration specifiers
/usr/include/bits/types.h:42: error: both 'short' and 'char' in declaration specifiers
/usr/include/bits/types.h:43: error: both 'short' and 'char' in declaration specifiers
.................................................
so and so 

Actually what is happening inside stdio.h ?

Answer 1

There are defined variables of type short int, long int and so on, which obviously fails when you change them through define to short char and long char.

Redefining basic C types is usually not a good idea.