Suppose that only 80% of the student records from exercise 16.28 have a value for phone, 85% for major_dept_code, 15% for minor_dept_code, and 90% for degree_program; and suppose that we use a variable-length record file. each record has a 1-byte field type for each field in the record, plus the 1-byte deletion marker and a 1-byte end-of-record marker. suppose that we use a spanned record organization, where each block has a 5-byte pointer to the next block (this space is not used for record storage). a. calculate the average record length r in bytes. b. calculate the number of blocks needed for the file.

Consider the following statements: struct nametype{string first; string last; }; struct coursetype{string name; int callnum; int credits; char grade; }; struct studenttype{nametype name; double gpa; coursetype course; }; studenttype student; studenttype classlist[100]; coursetype course; nametype name; mark the following statements as valid or invalid. if a statement is invalid, explain why. a.) student. course. callnum = "csc230"; b.) cin > > student. name; c.) classlist[0] = name; d.) classlist[1].gpa = 3.45; e.) name = classlist[15].name; f.) student. name = name; g.) cout < < classlist[10] < < endl; h.) for (int j = 0; j < 100; j++)classlist[j].name = name; i.) classlist. course. credits = 3; j.) course = studenttype. course;