chapter 3

• Abstraction and Encapsulation are key concepts in object-oriented programming.
• The StackOfIntegers class is implemented.
• Abstraction in object-oriented programming means to separate class implementation from the use of the class, allowing the creator of the class to provide a description of the class and let the user know how the class can be used.
• Encapsulation in object-oriented programming hides the detail of implementation from the user, allowing the user to use the class through the contract of the class.
• The amount of this loan can be accessed through the getLoanAmount() method.
• The annual interest rate of this loan can be accessed through the getAnnualInterestRate() method.
• The annual interest rate of the loan is a double with a default value of 2.5.
• The monthly payment of this loan can be accessed through the getMonthlyPayment() method.
• The date of the creation of this loan can be accessed through the getLoanDate() method.
• The number of years of this loan can be accessed through the getNumberOfYears() method.
• A Loan object is constructed with the default values for the annual interest rate, number of years, and loan amount.
• The date of the creation of this loan is a Date.
• The number of years for the loan is an int with a default value of 1.
• The loan amount is a double with a default value of 1000.
• The total payment of this loan can be accessed through the getTotalPayment() method.
• Aggregation may exist between objects of the same class.
• A BMI object can be created with the specified name, weight, height, and a default age of 20.
• The BMI status (e.g., normal, overweight, etc.) can be returned from a BMI object.
• Association is a general binary relationship that describes an activity between two classes.
• The subject object in an aggregation relationship is called an aggregated object and its class an aggregated class.
• Aggregation models has-a relationships and represents an ownership relationship between two objects.
• An aggregation relationship is usually represented as a data field in the aggregating class.
• The weight of a person in pounds and the height of a person in inches create a BMI object with the specified name, age, weight, and height.
• Composition is a special case of the aggregation relationship.
• The owner object in an aggregation relationship is called an aggregating object and its class an aggregating class.
• Aggregation and composition relationships are represented using classes in similar ways, many texts don’t differentiate them and call both compositions.