/in/foo.cc: In function 'void in()':
/in/foo.cc:25:10: warning: unused variable 't0' [-Wunused-variable]
      int t0,t1,t2,t3;
          ^~
/in/foo.cc: In function 'int main()':
/in/foo.cc:117:21: warning: 'head' may be used uninitialized in this function [-Wmaybe-uninitialized]
    else a[i].rclas=i-head+1;  
                    ~^~~~~