Logical operators in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the logical AND operator (&&) do in C#?

The logical AND operator (&&) returns true only if both conditions on its sides are true. If either condition is false, the result is false.

beginner

Explain the logical OR operator (||) in C#.

The logical OR operator (||) returns true if at least one of the conditions is true. It returns false only if both conditions are false.

beginner

What is the purpose of the logical NOT operator (!) in C#?

The logical NOT operator (!) reverses the value of a boolean expression. If the expression is true, ! makes it false, and vice versa.

intermediate

How does short-circuit evaluation work with && and || operators?

In C#, && and || use short-circuit evaluation. For &&, if the first condition is false, the second is not checked because the result is already false. For ||, if the first condition is true, the second is not checked because the result is already true.

intermediate

What is the difference between & and && in C#?

The & operator is a logical AND that always evaluates both sides, while && is a conditional AND that stops evaluating if the first side is false (short-circuit). & can also be used as a bitwise AND.

What will the expression (true && false) evaluate to in C#?

A true

B error

C null

D false

The && operator returns true only if both sides are true. Here, one side is false, so the result is false.

Which operator reverses the boolean value of an expression?

A !

B ||

C &&

D &

The ! operator is the logical NOT operator that reverses true to false and false to true.

What does the expression (false || true) return?

A false

B true

C null

D error

The || operator returns true if at least one side is true. Here, the second side is true, so the result is true.

Which statement about short-circuit evaluation is true?

A && always evaluates both sides

B || always evaluates both sides

C && stops evaluating if the first side is false

D ! stops evaluating if the expression is true

&& uses short-circuit evaluation and stops if the first condition is false because the whole expression cannot be true.

What is the difference between & and && in C#?

A & is bitwise AND, && is logical AND with short-circuit

B & is logical OR, && is logical AND

C & and && are the same

D & is logical NOT, && is logical OR

& can be bitwise AND or logical AND without short-circuit; && is logical AND with short-circuit evaluation.

Describe how the logical AND (&&) and OR (||) operators work in C#.

Think about when the evaluation stops early.

Explain the difference between & and && operators in C#.

Consider evaluation and bitwise use.