/in/foo.cc: In function 'int main()':
/in/foo.cc:31:7: warning: unused variable 'x' [-Wunused-variable]
   int x=0;
       ^
/in/foo.cc: In function 'bool A(student, student)':
/in/foo.cc:23:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^