Course of Raku / Essentials / Typed variables / Exercises / Examine the result of prompt — Numbers

Solution: Examine the result of prompt — Numbers

Code

Here is the complete program that solves the problem and prints both the entered value and its type.

my $n = prompt 'Enter a number: ';
say $n;
say $n.WHAT;

🦋 You can find the source code in the file prompt-numbers.raku.

Test runs

Run the program several times and enter the numbers of different types.

Integers

Let us try integers first, both positive and negative.

$ raku exercises/what/prompt-numbers.raku
Enter a number: 10
10
(IntStr)

The type of the result is IntStr. This is a built-in type that has the features of both Int and Str.

Rational numbers

Now let us try a rational number. Remember that in Raku, notation with a decimal dot creates a Rat number rather than a floating-point number.

$ raku exercises/what/prompt-numbers.raku
Enter a number: 3.14
3.14
(RatStr)

This time, the program says that the type of data in $n is RatStr, which stands for a combined type of both Rat and Str.

Floating-point numbers

Finally, try a number in the scientific notation. You should be able to guess the output at this point.

$ raku exercises/what/prompt-numbers.raku
Enter a number: 5e-14
5e-14
(NumStr)

Indeed, the new value is of the NumStr type.

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