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JavaScript

Posted by Marc Amil
Marc Amil
Courses Plus Student 928 Points

Different equation but seems to work, I don't know why.

function mathRandom(number1, number2) { return Math.floor(Math.random() * (number1- number2)+ number2) + 1; } document.write(mathRandom(100,99));

using different numbers it seems to work, but using this example of number1 = 100 number2 = 99 (100- 99) + 99) +1 1+99 +1 =101 and since Math.random can produce a value of 0 but not including 1 and math floor rounds it down it will produce a value of 100, which in that aspect I get. However, I do not get in which part of this code it considers the lower number for the range, wouldn't it just go from 0 to 101

Swaumu Juma
.a{fill-rule:evenodd;}techdegree
Swaumu Juma
Full Stack JavaScript Techdegree Student 10,564 Points
  • number1 = 100
  • number2 = 99
  • from your equation: Math.floor(Math.random() * (number1- number2)+ number2) + 1;
  • lets say: var sj = Math.random() * (100-99) + 99
  • therefore: sj = Math.random() * 100
  • Math.floor(sj) + 1;
  • therefore this is what you have: Math.floor(Math.random() * 100) + 1
  • remember the +1 make your random number to start from one and not zero anymore

1 Answer

Steven Parker
Steven Parker
243,200 Points
Steven Parker
Steven Parker
243,200 Points

That formula is a little off, the classic formula for random numbers in a range is:

Math.floor(Math.random() * (number1 - number2 + 1)) + number2

where "number1" is the largest number in the range, and "number2" is the smallest.

Supplying 100 and 99 as the numbers will yield either a 99 or 100 every time, as expected.