A Boolean variable has exactly two values.
A Boolean variable, named after George Boole (1815-1864) who invented mathematical logic and defined Boolean algebra, is a fundamental data type used in computer science and logic. As stated in the reference, a variable of the primitive data type boolean can have two values: true and false (Boolean literals).
The Two Boolean Values
The two distinct values a Boolean variable can hold represent binary states, typically corresponding to truth and falsehood:
- true: Represents a state of truth, affirmation, or 'on'.
- false: Represents a state of falsehood, negation, or 'off'.
These are the only two possible states for a Boolean variable.
Understanding Boolean Logic
The concept of having only two possible values is core to Boolean logic, which is the basis for all modern digital computers. This simple binary system allows computers to make decisions and control program flow.
Think of it like a light switch, which can only be in one of two states:
- On (
true) - Off (
false)
Boolean variables are essential for:
- Evaluating conditions (e.g.,
if (isReady == true)) - Controlling loops (e.g.,
while (isRunning)) - Representing states that are either one thing or the other (e.g.,
isAdmin,isVisible).
Here's a simple representation:
| Value | Meaning | Common Usage Example |
|---|---|---|
true |
Represents truth/yes/on | Condition is met |
false |
Represents falsehood/no/off | Condition is not met |
In programming languages, Boolean variables store these true or false values directly.
