/in/foo.c: In function 'main':
/in/foo.c:15:9: error: too few arguments to function 'qsort'
         qsort(a,n,sizeof(int));
         ^~~~~
In file included from /in/foo.c:2:0:
/usr/include/stdlib.h:725:13: note: declared here
 extern void qsort (void *__base, size_t __nmemb, size_t __size,
             ^~~~~
/in/foo.c:17:9: error: expected ';' before 'f'
         f[0]=1;
         ^
/in/foo.c:28:13: error: expected ';' before '}' token
             }
             ^
/in/foo.c:30:9: warning: implicit declaration of function 'print' [-Wimplicit-function-declaration]
         print("%d\n",ans);
         ^~~~~