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JavaScript JavaScript Basics (Retired) Working With Numbers The Random Challenge Solution

Gloria Gasbarra
Gloria Gasbarra
4,487 Points
Posted by Gloria Gasbarra
Gloria Gasbarra
4,487 Points

My code is really different, but it works. What's wrong?

var first = prompt("Which is the first number?");

var last = prompt("Which is the last number?");

var random = (parseInt (Math.random() * (first, last)) + 1 );

document.write(random + " is a number between " + first + " and " + last);

2 Answers

A X
A X
12,842 Points

Hi Gloria, You're right your code works as long as you "play fairly"...like I set out to break your code, and I put in the first number of 0 and the last number of 0 and got this result:

Random Number Generator 1 is a number between 0 and 0 (which is False)

I also tried 0 and 1:

Random Number Generator 1 is a number between 0 and 1 (which is False)

I also tried strings, and floats:

Random Number Generator NaN is a number between one and two

Random Number Generator 1 is a number between .1 and .3

I also tried negative numbers:

Random Number Generator 0 is a number between -1 and -2 (which is False)

So you could look at this result a few ways, like oh geez, I have ways of breaking the program! Or you could say, that's ok I like the way the program runs..... but mainly there's nothing "wrong" with what you did if you don't want to account for my ways of breaking the program. The Math.floor in the video is attempting to prevent breaking the program from some of the breaks I tried from your version.

Gloria Gasbarra
Gloria Gasbarra
4,487 Points
Gloria Gasbarra
Gloria Gasbarra
4,487 Points

Thanks @nekilof, you're great! I didn't try. Then your text I tried with the video's code...

var input1 = prompt("Please type a starting number");

var bottomNumber = parseInt(input1);

var input2 = prompt("Please type a number");

var topNumber = parseInt(input2);

var randomNumber = Math.floor(Math.random() * (topNumber - bottomNumber + 1) + 1);

var message = "<p>" + randomNumber + " is a number between 1 and " + topNumber + " .</p>";

document.write(message);

I tried 0 and 1: Random Number Generator 2 is a number between 1 and 1 .

I tried -1 and -2: Random Number Generator 1 is a number between 1 and -2 .

I tried 20 and 30: Random Number Generator 4 is a number between 1 and 30 .

(The counting starts always from the number 1)

I don't know... What do you think?

Abhijit Das
Abhijit Das
5,022 Points
Abhijit Das
Abhijit Das
5,022 Points

if I am not wrong isn't should be like as the video code: var randomNumber = Math.floor(Math.random() * (topNumber - bottomNumber + 1) + bottomNumber); instead the +1 at last place?