/in/foo.c: In function 'main':
/in/foo.c:9:2: error: 'd0' undeclared (first use in this function)
  d0
  ^~
/in/foo.c:9:2: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:10:2: error: expected ';' before '{' token
  {
  ^
/in/foo.c:5:6: warning: variable 'x' set but not used [-Wunused-but-set-variable]
  int x,i,j;
      ^