/in/foo.cc: In function 'int main()':
/in/foo.cc:20:10: warning: unused variable 'key2' [-Wunused-variable]
  int key,key2,now2=-1;
          ^~~~
/in/foo.cc:34:23: warning: 'key' may be used uninitialized in this function [-Wmaybe-uninitialized]
    cout<<b[(a[i]-'a'+1+key)%26+1];
            ~~~~~~~~~~~^~~~~