/in/foo.c:1:9: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
 include <stdio.h>
         ^
In file included from /in/foo.c:2:0:
/usr/include/string.h:43:8: error: unknown type name 'size_t'
        size_t __n) __THROW __nonnull ((1, 2));
        ^~~~~~
/usr/include/string.h:46:56: error: unknown type name 'size_t'
 extern void *memmove (void *__dest, const void *__src, size_t __n)
                                                        ^~~~~~
/usr/include/string.h:62:42: error: unknown type name 'size_t'
 extern void *memset (void *__s, int __c, size_t __n) __THROW __nonnull ((1));
                                          ^~~~~~
/usr/include/string.h:65:56: error: unknown type name 'size_t'
 extern int memcmp (const void *__s1, const void *__s2, size_t __n)
                                                        ^~~~~~
/usr/include/string.h:92:48: error: unknown type name 'size_t'
 extern void *memchr (const void *__s, int __c, size_t __n)
                                                ^~~~~~
/usr/include/string.h:129:39: error: unknown type name 'size_t'
         const char *__restrict __src, size_t __n)
                                       ^~~~~~
/usr/include/string.h:137:9: error: unknown type name 'size_t'
         size_t __n) __THROW __nonnull ((1, 2));
         ^~~~~~
/usr/include/string.h:143:57: error: unknown type name 'size_t'
 extern int strncmp (const char *__s1, const char *__s2, size_t __n)
                                                         ^~~~~~
/usr/include/string.h:150:8: error: unknown type name 'size_t'
 extern size_t strxfrm (char *__restrict __dest,
        ^~~~~~
/usr/include/string.h:151:40: error: unknown type name 'size_t'
          const char *__restrict __src, size_t __n)
                                        ^~~~~~
/usr/include/string.h:280:8: error: unknown type name 'size_t'
 extern size_t strcspn (const char *__s, const char *__reject)
        ^~~~~~
/usr/include/string.h:284:8: error: unknown type name 'size_t'
 extern size_t strspn (const char *__s, const char *__accept)
        ^~~~~~
/usr/include/string.h:394:8: error: unknown type name 'size_t'
 extern size_t strlen (const char *__s)
        ^~~~~~
/usr/include/string.h:446:33: error: unknown type name 'size_t'
 extern void __bzero (void *__s, size_t __n) __THROW __nonnull ((1));
                                 ^~~~~~
/in/foo.c: In function 'main':
/in/foo.c:6:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%5s", n);
  ^~~~~
/in/foo.c:6:2: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:6:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:8:2: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
  printf("%d\n", c);
  ^~~~~~
/in/foo.c:8:2: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:8:2: note: include '<stdio.h>' or provide a declaration of 'printf'