C# Booleans
C# Booleans
Very often, in programming, you will need a data type that can only have one of two values, like:
- YES / NO
- ON / OFF
- TRUE / FALSE
For this, C# has a bool
data type, which can take the values true
or false
.
Boolean Values
A boolean type is declared with the bool
keyword and can only take the values true
or false
:
Example
bool isCSharpFun = true;
bool isFishTasty = false;
Console.WriteLine(isCSharpFun); // Outputs True
Console.WriteLine(isFishTasty); // Outputs False
However, it is more common to return boolean values from boolean expressions, for conditional testing (see below).
Boolean Expression
A Boolean expression is a C# expression that returns a Boolean value: True
or False
.
You can use a comparison operator, such as the greater than (>
) operator to find out if an expression (or a variable) is true:
Example
int x = 10;
int y = 9;
Console.WriteLine(x > y); // returns True, because 10 is higher than 9
Or even easier:
In the examples below, we use the equal to (==
) operator to evaluate an expression:
Example
int x = 10;
Console.WriteLine(x == 10); // returns True, because the value of x is equal to 10
The boolean value of an expression is the basis for all C# comparisons and conditions.
You will learn more about conditions in the next chapter.