C++ is an object-oriented language. An object is an abstraction of state and behavior. Imagine real-world objects, such as a light switch. We can describe various attributes of the switch as states, for example: is it on or off? What is the rated voltage? In which room is it located? We can also describe the behavior of the switch, such as: does it switch from one state (on) to another state (off)? Is it a dimmer switch that has many other states between on and off?