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Random Number Challenge – Two Numbers Solution
4:06Update the random number program to ask for two numbers, then provide a random number between the two.
All right now I will show you how I
solved the second part of this challenge.
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The program should ask for two numbers and
provide a random number between the two.
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First, I need to ask for another input.
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I will declare a variable named
inputLow and assign it the prompt method.
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I'll pass it the string "Please
provide your lowest number".
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Then change the input high message to
Please provide your highest number.
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The string value stored and input low
needs to be converted into a number type.
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I'll store that number value
in a variable named lowNumber.
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I'll again use the parseInt method
to convert the string to an integer.
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The variable lowNumber represents
the lowest possible random number.
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So now I need to change how
the random number gets generated.
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For example, instead of being a number
from 1 to the value stored in highNumber,
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it needs to generate a number
from lowNumber to highNumber.
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To achieve this, I'll change the number
being multiplied by Math.random.
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I'll subtract the lowNumber
from the highNumber and
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add 1 to it with
highNumber- lowNumber + 1.
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And then add the lowNumber to
the return value of Math.floor.
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So this generates a number from 0 to
the difference between the highest and
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lowest number plus 1.
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For example,
if I want a random number from 10 to 25.
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Well, 25 minus 10 plus 1 is 16.
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So this would generate a random number
from 0 up to but not including 16.
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By providing that value to Math.floor,
I'll get a random number from 0 to 15.
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Then, I add the lowest number which
produces the number from 10 to 25.
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Now, don't worry at all if
the math still seems confusing.
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At least now you have an equation
that does the math for you.
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Next, I'll update the random number
console message by inserting the value of
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the low number variable into the string.
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And I'll update the message in the else
clause to You need to provide two numbers.
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Try again.
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Finally, I'll update the condition and
the if statement.
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This time I need to check if
the values stored in lowNumber and
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the value in highNumber is a true number.
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In other words, make sure that
both are not NaN or not a number.
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I'll use the logical and operator,
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you learned about in a previous
course in the condition like this.
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lowNumber && highNumber.
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If even one of these is not a number,
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the entire condition evaluates to false
and the code in the else clause runs.
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Okay, let's see how this works now.
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I'll save my file, refresh the page.
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I'll enter the lowest number,
let's say 10 and the highest number 25.
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The console outputs the message 14 is
a random number between 10 and 25.
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Now, I'll try entering
a value like three then 15.
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The console outputs,
You need to provide two numbers.
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Try again, good.
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Nice work with the addition
of numeric data types and
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the Math object to your toolset,
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you're well on your way to programming
some pretty powerful applications.
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To practice more with numbers and math,
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be sure to review the resources
posted in the teacher's notes.
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And we're here to help.
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So if you have questions about
anything covered in this course,
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feel free to reach out to other students
in the community or the treehouse staff.
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Thanks everyone and happy coding.
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