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## A random integer from min to max

importance: 2

Create a function `randomInteger(min, max)` that generates a random integer number from `min` to `max` including both `min` and `max` as possible values.

Any number from the interval `min..max` must appear with the same probability.

Examples of its work:

``````alert( randomInteger(1, 5) ); // 1
alert( randomInteger(1, 5) ); // 3
alert( randomInteger(1, 5) ); // 5``````

You can use the solution of the previous task as the base.

#### The simple but wrong solution

The simplest, but wrong solution would be to generate a value from `min` to `max` and round it:

``````function randomInteger(min, max) {
let rand = min + Math.random() * (max - min);
return Math.round(rand);
}

The function works, but it is incorrect. The probability to get edge values `min` and `max` is two times less than any other.

If you run the example above many times, you would easily see that `2` appears the most often.

That happens because `Math.round()` gets random numbers from the interval `1..3` and rounds them as follows:

``````values from 1    ... to 1.4999999999  become 1
values from 1.5  ... to 2.4999999999  become 2
values from 2.5  ... to 2.9999999999  become 3``````

Now we can clearly see that `1` gets twice less values than `2`. And the same with `3`.

#### The correct solution

There are many correct solutions to the task. One of them is to adjust interval borders. To ensure the same intervals, we can generate values from `0.5 to 3.5`, thus adding the required probabilities to the edges:

``````function randomInteger(min, max) {
// now rand is from  (min-0.5) to (max+0.5)
let rand = min - 0.5 + Math.random() * (max - min + 1);
return Math.round(rand);
}

An alternative way could be to use `Math.floor` for a random number from `min` to `max+1`:

``````function randomInteger(min, max) {
// here rand is from min to (max+1)
let rand = min + Math.random() * (max + 1 - min);
return Math.floor(rand);
}

Now all intervals are mapped this way:

``````values from 1  ... to 1.9999999999  become 1
values from 2  ... to 2.9999999999  become 2
values from 3  ... to 3.9999999999  become 3``````

All intervals have the same length, making the final distribution uniform.