Logical operators in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are the three main logical operators in C++?

The three main logical operators in C++ are:<br>&& (logical AND), || (logical OR), and ! (logical NOT).

beginner

Explain the behavior of the logical AND (&&) operator.

The logical AND (&&) operator returns true only if both conditions on its left and right are true. If either condition is false, it returns false.

beginner

What does the logical OR (||) operator do?

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

How does the logical NOT (!) operator work?

The logical NOT (!) operator reverses the truth value of a condition. If the condition is true, ! makes it false; if false, ! makes it true.

intermediate

What is short-circuit evaluation in logical operators?

Short-circuit evaluation means that in expressions using && or ||, evaluation stops as soon as the result is known. For &&, if the first condition is false, the second is not checked. For ||, if the first condition is true, the second is not checked.

Which logical operator returns true only if both conditions are true?

A && (AND)

B || (OR)

C ! (NOT)

D ^ (XOR)

The && operator returns true only if both conditions are true.

What is the result of the expression: !(true && false)?

A true

B false

C undefined

D error

true && false is false, and !false is true.

In C++, what does the || operator do?

A Negates the condition

B Returns true if both conditions are true

C Returns false if any condition is true

D Returns true if at least one condition is true

The || operator returns true if at least one condition is true.

What happens in short-circuit evaluation with the expression: false && (someFunction())?

A someFunction() is called

B Both conditions are evaluated

C someFunction() is not called

D Error occurs

Because the first condition is false, && stops and does not call someFunction().

Which operator reverses the truth value of a condition?

A ||

B !

C &&

D ==

The ! operator negates or reverses the truth value.

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

Think about when each operator returns true or false.

Explain what short-circuit evaluation means and why it is useful in logical expressions.

Imagine checking conditions one by one and stopping when you know the answer.