CODEWITHSUNDEEP
javascript
Kyle Wilcox
Kyle Wilcox

Reputation: 13

Javascript - How to make a bunch of variables have a random number different from other variables

I am making a STEM game for a school and I'm having it randomly pick question numbers. There are 30 questions but I only want 20 of that 30 to be used. I need it to randomly pick a number from 1-30 (No 0) and set each random number to a certain variable. But I can't figure out how to make it so that it doesn't use the same number twice. Any help?

Heres the code I got so far:

function onLoad() {
 var N1 = Math.floor(Math.random() * 30) + 1;
 var N2 = Math.floor(Math.random() * 30) + 1;
 var N3 = 0;
 var N4 = 0;
 var N5 = 0;
 var N6 = 0;
 var N7 = 0;
 var N8 = 0;
 var N9 = 0;
 var N10 = 0;
 var N11 = 0;
 var N12 = 0;
 var N13 = 0;
 var N14 = 0;
 var N15 = 0;
 var N16 = 0;
 var N17 = 0;
 var N18 = 0;
 var N19 = 0;
 var N20 = 0;
 
 //Make it so each one is checked so that the same question is not used
 //N1 is gonna be the first question and does not need to be check
 //N2-N20 need to make sure they aren't the same as N1-N20
 
 if (N2 == N1) {
  N2 = Math.floor(Math.random() * 30) + 1;
 }
}

I have a good idea of the checker but there is also the chance that if it is the same in the beginning and I have it generate a new number it'll be the same number and mess up the game.

Upvotes: 1

Views: 123

Answers (1)

castletheperson
castletheperson

Reputation: 33486

First, you need to generate an array of the numbers 1-30, then shuffle the array, and then you can retrieve the first 20 numbers in the array.

function getRandomQuestionNumbers() {
  var numbers = [];
  for (var i = 1; i <= 30; i++) {
    numbers.push(i);
  }
  shuffle(numbers);
  return numbers.slice(0, 20);
}

For a good shuffle function, use one of the top answers to this question.

Upvotes: 1

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