CSharp/C# Tutorial - C# Conditional Operators

The && and || operators test for and and or conditions.

! operator expresses not.

The following code creates a boolean expression with and, not and or operators.

!cloudy && (WeekDay || ThanksGiving); 

Short-circuit evaluation

The && and || operators short-circuit evaluation when possible.

In the preceding example, if it is cloudy, the expression (WeekDay || ThanksGiving) is not even evaluated.

Short-circuiting allows the following expressions to run without throwing a NullReferenceException:

if (reference != null && reference.Length > 0) ... 

The & and | operators also test for and and or conditions:

return !cloudy & (WeekDay | ThanksGiving); 

& and | operators do not short-circuit.

? conditional operator

The conditional operator has the form q ? a : b, where if condition q is true, a is evaluated, else b is evaluated. For example:

static int Max (int a, int b) { 
    return (a > b) ? a : b;