/in/foo.c: In function 'output':
/in/foo.c:5:1: error: expected ';' before 'for'
 for(i=0;i<y;i++)
 ^~~
/in/foo.c:7:10: error: expected expression before ']' token
 return a[];
          ^
/in/foo.c:8:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^