CMPS 222 - Homework 3

Homework 3 - Operator Overloading

Due: Wednesday February 1, 2012 at 5:30pm

Note: Since Midterm 1 is on Monday February 6th, the last day to turn this assignment in LATE is Friday February 3rd, so the solutions can be posted for study over the weekend.

Coding Conventions

Use the same coding conventions as described in Homework 1. Additionally, make sure to indent each section of the class in the class definition.

Assignment

For this assignment, you will be modifying the Score class from Lab 3 to support a full range of operators.

Add the following constructors and operators to the Score class:

Conversion constructor for double. This constructor will take one double parameter. If the double is negative, set the millions and billions counters to 0. If the double is positive, do the following conversion:
```
  while the double is greater than THRESHOLD 
    increment the billions counter
    subtract THRESHOLD from the double
  end-while
  set the millions counter to the double using integer typecasting
```
Copy constructor. This constructor will take a const reference to another Score object. It will copy the source's millions and billions counter to the current Score object.
Assignment operator, =. Modify the provided assignment operator to support chained assignment. Instead of being a void function, it will return a Score reference. After assigning the counters, it will return the dereferenced this pointer.

Subtraction operator, -. Subtract the value of the RHS score from the LHS score. Use the following logic to do subtraction:

  declare a Score object called temp
  if RHS Score is greater than LHS score
    set temp's millions and billions counter to 0
  else
    if RHS's millions counter is greater than LHS's millions counter
      subtract 1 from LHS's billions counter
      add 1billion to LHS's millions counter (borrow from the billions counter)
    end-if
    set temp's millions counter to LHS's millions counter - RHS's millions counter
    set temp's billions counter to LHS's billions counter - RHS's billions counter
  end-if
  return the temp object

Less-than operator, <. This function will compare two Score objects and return true if the left object has a lower score than the right object. Be sure with less-than (and all other relational operators) to compare both the billions and millions counters. For example, if left is 1 billion, 500 million and right is 2 billion, 300 million, then left is less than right even though left's millions are greater than right's millions.
Less-than-or-equal-to operator, <=. This function will compare two Score objects and return true if the left object has a score that is less than or equal to the right object.
Greater-than operator, >. This function will compare two Score objects and return true if the left object has a larger score than the right object.
Greater-than-or-equal-to operator, >=. This function will compare two Score objects and return true if the left object has a score that is greater than or equal to the right object.
Equality operator, ==. This function will compare two Score objects and return true if the left object has a score that is equal to the right object.
Inequality operator, !=. This function will compare two Score objects and return true if the left object has a score that is NOT equal to the right object.

Main Function

Your main() function is going to be a driver function that tests all of the operators and constructors you have added to the class. Note how the main() function for Lab 3 tests input, output, converting an integer, addition, the default constructor and so on. You will need to add additional testing for all of the above features.

In particular, your main function should test the following:

Test the double conversion operator by reading a double from the keyboard and creating a new Score variable from that double. You should then cout the new Score object to verify that it converted the double correctly. This is similar to the following lines from Lab 3 (but for doubles):
```
      int i;
      cout << "Enter a number for 'a': ";
      cin >> i;
      Score a(i);
      cout << "'a' is now " << a << endl;
```
Test the copy constructor by declaring a new Score variable and passing it an existing Score variable. Then cout both Score variables to confirm that they are identical.
Test the assignment operator by assigning one Score variable to another Score variable. Then cout both Score variables to confirm that they are identical.
Test the subtraction operator by subtracting one Score variable by another Score variable. Then output the result to confirm that subtraction is working correctly. Important: Subtraction should NEVER result in a negative score.
Test all the relational operators with a series of if-else statements comparing two Score variables. For example, the following code tests the equality operator:
```
      if(a == b)
        cout << "'a' and 'b' are equal.\n";
      else
        cout << "'a' and 'b' are NOT equal.\n";
```

Email your complete Score class and main function to me.