: error C2064: term does not evaluate to a function taking 1 arguments : error C2227: left of '->name' must point to class/struct/union/generic type

how do i fix this so this error doesn't happen

    for(int index = 0; index < (numStudents); index++)
 {
     if (student(index + 1)->score >= 90 )
      student(index + 1)->grade = 'A';
        else if (student(index + 1)->score >= 80 )
   student(index + 1)->grade = 'B';
     else if (student(index + 1)->score >= 70 )
   student(index + 1)->grade = 'C';
  else if (student(index + 1)->score >= 60 )
   student(index + 1)->grade = 'D';
  else 
   student(index + 1)->grade = 'F';
 }