display            10 movingobject.c                               void(*display)(movingobject* obj), 
display            17 movingobject.c   ret->display = display;
display            34 movingobject.c   mobj->display(mobj);
display            13 movingobject.h   void (*display)(struct movingobject* obj);
display            22 movingobject.h                               void(*display)(movingobject* obj),