/in/foo.c: In function 'main':
/in/foo.c:35:23: error: 'k' undeclared (first use in this function)
  {if (function(mouse, k)==x)
                       ^
/in/foo.c:35:23: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:35:27: error: 'x' undeclared (first use in this function)
  {if (function(mouse, k)==x)
                           ^