Course of Raku / Essentials / Variables and data types essentials / Boolean type / Exercises / Double negation

Solution: Double negation

Let us extend the program to solve the second part of the exercise and reuse the same variable:

Code

my $value = False;
say !!$value;

$value = True;
say !!$value;

🦋 You can find the full code in the file double-negation.raku.

Comments

Before running the program, let us think what it will print. There are two negation operators before the variable. They act as two negation operators. In the first case, the value is flipped from False to True, and then immediately flipped back from True to False. In the second case, the algorithm is the same: after two negations, we get the initial Boolean value.

Output

The program prints the following output, which confirms the above considerations:

$ raku exercises/booleans/double-negation.raku
False
True

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