/in/foo.cc: In function 'int main()':
/in/foo.cc:17:31: error: expected primary-expression before '[' token
   17 |                         st+=cy[i].t*b[i];
      |                               ^
/in/foo.cc:18:31: error: expected primary-expression before '[' token
   18 |                         sv+=cy[i].v*b[i];
      |                               ^