This lab will help you learn how to use Java classes and objects.

The objectives of this week are following:

• Programming abstraction.
• Overloading constructor.
• Identify public and private interfaces.
• Simple Data encapsulation and data validation.
• Simple string matching using regular expression.

To complete the homework you need to meet following requirements:

• Write the classes according the specifications.
• Write a readable, sensible, usable, beautiful code.
• Pass all the unit tests.

Requirement:

1. For floating point number, only the five digits after dot will be considered in the result. The sixth and so on digit should be rounded to the nearest number, 5 will be always round up.

2. For division operation, it must throw an exception when divide by zero.

3. For username, it has to be alphanumeric only, no symbols. The first character must be an english alphabet. The username has to be at least eight character in length. The method setUserName() must return false when an invalid name is assigned.

4. For password, it has to be alphanumeric only, no symbols. There must be at least one number and one english alphabet in the password. Also there must be at least one capitalized character and one non-capitalized character. The length must be at least 12. The method setPassword() must return false when an invalid password is assigned.