/in/foo.c: In function 'main':
/in/foo.c:11:26: warning: left-hand operand of comma expression has no effect [-Wunused-value]
  for(pa=a+1,pb=b+1;pa<a+n,pb<b+n;pa++,pb++)
                          ^
/in/foo.c: In function 'gys':
/in/foo.c:40:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^