For instance suppose there is a class which represents a car. A car has a make, a model, a year, a maximum speed, a weight, a price, a number of passengers it can carry, four wheels, either two or four doors and many other properties you can represent with member variables. Here's how you might write a class definition for a car:
class Car {
String make;
String model;
int year;
int max_speed;
int weight
float price;
int num_passengers;
int num_wheels = 4;
int num_doors;
}
Obviously this doesn't exhaust everything there is to say about a car. Which properties you choose to include in your class depends on your application.