/in/foo.cc: In function 'void Output(int*, int)':
/in/foo.cc:7:5: warning: value computed is not used [-Wunused-value]
  a[i];
  ~~~^
/in/foo.cc:7:5: warning: statement has no effect [-Wunused-value]
/in/foo.cc: In function 'int main()':
/in/foo.cc:39:6: warning: unused variable 'cnt' [-Wunused-variable]
  int cnt=0;
      ^~~