FAQ: Logical Operators - Logical Operator:!

Frequently Asked Questions C++ FAQ
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Community%20FAQs%20on%20Codecademy%20Exercises
Community%20FAQs%20on%20Codecademy%20Exercises1000×208 141 KB

This community-built FAQ covers the “Logical Operator: !” exercise from the lesson “Logical Operators”.

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This exercise can be found in the following Codecademy content:

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FAQs on the exercise Logical Operator: !

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2

There seems to be a bug, in that if not is used instead of !, the task marker returns a cross instead of a checkmark, even though the output in the terminal is the same for both logical operators.

Not a logical operator eh
Not a logical operator eh1392×734 43.1 KB

Exclamation mark
Exclamation mark1372×552 32.5 KB

3

i really couldn’t understand this one,can someone give me a quick help,this “not” option i didn’t understand anything,not even the purpose :’)

4

Is syntax you type ! or not when you want the opposite of a variable. It is only for bool variables
eg: bool rainy = true;
you could type if(!rainy){ don’t pick an umbrella }

5

If logged_in is defined as false, then why would the instructions ask the output of !logged_in (true) to print “Try again”? Is it telling the user to try again only if they are logged in?

6

The exercise wants the string "Try again" to be printed only when the user is not logged in.
If the user is logged in, then no message should be printed.

In an if statement, the code inside the block is only executed if the condition inside the parentheses evaluates to true.

In the exercise, logged_in is false. Therefore, its negation !logged_in will be true.

Hence the condition

if (!logged_in) {

will evaluate to true and the code inside the block will be executed printing the string "Try again".

If logged_in were true (i.e. user was logged in), then its negation !logged_in would be false and the code inside the block will not be executed.

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