freeCodeCamp

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id	title	challengeType	videoUrl
cf1111c1c12feddfaeb2bdef	Generate Random Whole Numbers within a Range	1	https://scrimba.com/c/cm83yu6

Description

Instead of generating a random number between zero and a given number like we did before, we can generate a random number that falls within a range of two specific numbers. To do this, we'll define a minimum number min and a maximum number max. Here's the formula we'll use. Take a moment to read it and try to understand what this code is doing: Math.floor(Math.random() * (max - min + 1)) + min

Instructions

Create a function called randomRange that takes a range myMin and myMax and returns a random number that's greater than or equal to myMin, and is less than or equal to myMax, inclusive.

Tests

tests:
  - text: The lowest random number that can be generated by <code>randomRange</code> should be equal to your minimum number, <code>myMin</code>.
    testString: assert(calcMin === 5);
  - text: The highest random number that can be generated by <code>randomRange</code> should be equal to your maximum number, <code>myMax</code>.
    testString: assert(calcMax === 15);
  - text: The random number generated by <code>randomRange</code> should be an integer, not a decimal.
    testString: assert(randomRange(0,1) % 1 === 0 );
  - text: <code>randomRange</code> should use both <code>myMax</code> and <code>myMin</code>, and return a random number in your range.
    testString: assert((function(){if(code.match(/myMax/g).length > 1 && code.match(/myMin/g).length > 2 && code.match(/Math.floor/g) && code.match(/Math.random/g)){return true;}else{return false;}})());

Challenge Seed

// Example
function ourRandomRange(ourMin, ourMax) {

  return Math.floor(Math.random() * (ourMax - ourMin + 1)) + ourMin;
}

ourRandomRange(1, 9);

// Only change code below this line.

function randomRange(myMin, myMax) {

  return 0; // Change this line

}

// Change these values to test your function
var myRandom = randomRange(5, 15);

After Test

var calcMin = 100;
var calcMax = -100;
for(var i = 0; i < 100; i++) {
  var result = randomRange(5,15);
  calcMin = Math.min(calcMin, result);
  calcMax = Math.max(calcMax, result);
}
(function(){
  if(typeof myRandom === 'number') {
    return "myRandom = " + myRandom;
  } else {
    return "myRandom undefined";
  }
})()

Solution

function randomRange(myMin, myMax) {
  return Math.floor(Math.random() * (myMax - myMin + 1)) + myMin;
}

2.8 KiB Raw Blame History