/in/foo.c: In function 'main':
/in/foo.c:22:20: error: 'a' undeclared (first use in this function)
       {scanf("%d",&a[i]); }
                    ^
/in/foo.c:22:20: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c: In function 'buffer_left_move':
/in/foo.c:15:5: warning: control reaches end of non-void function [-Wreturn-type]
     }
     ^