/in/foo.cc: In function 'int main()':
/in/foo.cc:54:8: warning: unused variable 'x' [-Wunused-variable]
    int x=mid();
        ^
/in/foo.cc: In function 'int mid()':
/in/foo.cc:40:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^