CMPS 221 - Homework 7

Homework 7 - Basic Classes (Extra Credit)

Due: Saturday November 20, 2010 at 5:00pm

NOTE: Since this is an extra credit assignment, NO late assignments will be accepted. The solution will be posted Saturday evening so you can study it before the final on Monday November 22nd.

The purpose of this assignment is to modify Homework 6 to use classes instead of structures. Each class object will be a single student record for the course. Name your source code hw7.cpp.

The class should be called StudentRecord. It will have the following member variables:

A C-style string (character array) for the student's full name (you can choose the maximum name length, but make it reasonable such as 30 characters).
A C-style string for the student ID number (9 characters + 1 for the null character).
An integer array that stores 4 exam scores.
A double for the overall class grade. You will calculate this value based on the user input for exam scores. The overall grade will be the average of the exam scores.

The class will also have the following member functions:

Default constructor - Set the name and ID to the empty string (where the first character of the string is the null character, '\0'). Set each exam score and the overall class grade to 0.
Accessor functions for each member variable - Return the current value(s) for that member variable.
Mutator functions for each member variable - Pass the desired new value(s) as arguments to each function. If the input is acceptable, set the member variable and return true. Otherwise, return false to reject the input.
Output operator << (friend function) - Output the member variables (the current student information), using setw() or printf to set column widths on each field (e.g. use a column width of 10 for the student ID). The overall course grade should be printed with 2 decimal places of precision. A student record should resemble the following when printed:
```
John Doe             000561234   75   85   80   92      83.00%
```
This is similar to the printStudent function from Homework 6.
Input operator >> (friend function) - Prompt the user for each value. Read the user's input into a temporary variable and use the mutator function to try to set the value. Repeat asking the user for the value while the mutator function returns false (indicating the user's input was rejected because it violated the data constraints). After reading in all the exam scores, calculate and set the overall grade. This function is similar to the getStudent function from Homework 6.

You MUST enforce the following data constraints in the mutator function for each member variable. Return true when the passed values are acceptable and false when they are not.

There must be at least one character to the name (strlen() will return the number of characters in a C-style string).
There must be exactly 9 digits in the student ID. You must check that each character is a digit (the isdigit() function will be useful here).
Each exam score must be in the range of 0 to 100.

In main(), you will create an array of StudentRecords and use a menu to manipulate this array. As with Homework 6, each menu item will call a function, passing the array to the function. Unlike Homework 6 where the function called other global functions, your global functions for this assignment will call member functions inside the class.

As with Homework 6, the ONLY global variable allowed will be the maximum capacity of the array. ALL other variables MUST be local to their functions or the main() function.

Use the following menu for the program:

  Welcome to the StudentRecord Gradebook
  ======================================
  1.  Enter student data for the class
  2.  Print all student records
  3.  Print a single student record

  0.  Exit
  ======================================
  Enter selection:

You will be using a variety of functions to implement these options. Option 1 will call a global getAllStudents() function. Option 2 will check if student data has been entered. If there are students, it will call a global printAllStudents() function. If there are no students, it will remind the user to select Option 1 first. Option 3 will also check if student data has been entered and remind the user to select Option 1 first if there are no students. If there are students, Option 3 will call the global printSelectedStudent() function.

The required global functions are as follows:

getAllStudents - This is a void function. It will take two arguments: an array of StudentRecord objects and a by-reference integer for the size. It will prompt the user for the number of students to enter and verify that the number of students is between 0 and the maximum capacity of the array. It will then loop for each student record, calling the input operator function on each StudentRecord object.
printAllStudents - This is a void function. It will take two arguments: a constant array of StudentRecord objects and a by-value integer for size. For each record in the array, it will print the index number of that record (e.g. the current value of i) and then call the output operator function on that StudentRecord object. Note that you should also set a column width using either setw() or printf() when printing the index number. The output of this function should resemble the following:
```
Index   Name                ID          Exam Grades            Overall Grade
0       John Doe            000561234   75   85   80   92      83.00%
1       Jane Smith          999123456   80   86   89   90      86.25%
2       Bob Smith           999654321   85   86   85   91      86.75%
```
printSelectedStudent - This is a void function. It will take two arguments: a constant array of StudentRecord objects and a by-value integer for size. This function will ask the user for the index number of the student they wish to print. The program MUST verify that the index number is between 0 and size-1. If the index number is valid, call the output operator function for that index. Otherwise, print an error message to the user and exit the function (returning to the menu where they can attempt to print a selected student again by selecting Option 3 again). Do NOT have an input validation loop for the index number, just have an if-else statement.

Email your completed source code to me.