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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Random Number Challenge

Posted by Shivang Chaturvedi
Shivang Chaturvedi
2,600 Points

Here is my code

var num1  = parseInt(prompt("Enter the 1st Number"));
var num2 = parseInt(prompt("Enter the 2nd Number"));

function randomNumber(a, b)
{

  if(a > b)
  {
    var randomNum = Math.floor(Math.random() * (a - b + 1)) + b;  
    alert(randomNum);
  }

  else
  {
    var randomNum = Math.floor(Math.random() * (b - a + 1)) + a;  
    alert(randomNum);
  }

}
var numArgument = randomNumber(num1, num2);

Would love to know if anyone has a better way to do it.

4 Answers

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

Here's a possible alternative:

function randomNumber(a, b) {
  if (a > b) [a, b] = [b, a];
  return Math.floor(Math.random() * (b - a + 1)) + a;
}
var numArgument = randomNumber(
  parseInt(prompt("Enter the 1st Number")),
  parseInt(prompt("Enter the 2nd Number"))
);
alert(numArgument);

The argument swapping shown on the 2nd line makes use of a technique called destructuring assignment.

Also note that in the original code, randomNumber did not return anything, so the assignment of numArgument would always be "undefined". But if you add "return randomNum;" at the end of the function then operationally it will be identical to this code.

Shivang Chaturvedi
Shivang Chaturvedi
2,600 Points

Steven Parker .. Thank You for sharing this new technique. Its a wonderful piece of code. Can you please tell me more about this block: 

if (a > b) [a, b] = [b, a];

Its not getting around my head very clearly. What is [a, b] = [b, a] doing?

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

That's a destructuring assignment. As used here, it's just a quick way of swapping two values.

Shivang Chaturvedi
Shivang Chaturvedi
2,600 Points
Shivang Chaturvedi
Shivang Chaturvedi
2,600 Points

Hey Steven Parker .. I understood what it is doing!! Thanks..

rayjens code
rayjens code
882 Points
rayjens code
rayjens code
882 Points

hello. i cant understand, because it says generate random number not input number right? or i misunderstand the question? my mind is flying away the topic is starting to be harder >.<

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

The input is for the range of the random number. The formula picks a random number so it will never be less than the low number you give, and never higher than the high number you give. So for example, if you were to input the numbers 20 and 30, you're asking the computer to "pick any number between 20 and 30".

rayjens code
rayjens code
882 Points
rayjens code
rayjens code
882 Points

ahh i see . thanks for that bro. I feel harder to understand the topics, maybe the lecturer at this stage is so fast >.<