# Getting random numbers in Java

## Getting random numbers in Java

### Question

I would like to get a random value between 1 to 50 in Java.

How may I do that with the help of `Math.random();`

?

How do I bound the values that `Math.random()`

returns?

### Accepted Answer

The first solution is to use the `java.util.Random`

class:

```
import java.util.Random;
Random rand = new Random();
// Obtain a number between [0 - 49].
int n = rand.nextInt(50);
// Add 1 to the result to get a number from the required range
// (i.e., [1 - 50]).
n += 1;
```

Another solution is using `Math.random()`

:

```
double random = Math.random() * 49 + 1;
```

or

```
int random = (int)(Math.random() * 50 + 1);
```

### Popular Answer

```
int max = 50;
int min = 1;
```

## 1. Using **Math.random()**

```
double random = Math.random() * 49 + 1;
or
int random = (int )(Math.random() * 50 + 1);
```

This will give you value from 1 to 50 in case of int or 1.0 (inclusive) to 50.0 (exclusive) in case of double

Why?

random() method returns a random number between 0.0 and 0.9..., you multiply it by 50, so upper limit becomes 0.0 to 49.999... when you add 1, it becomes 1.0 to 50.999..., now when you truncate to int, you get 1 to 50. (thanks to @rup in comments). leepoint's awesome write-up on both the approaches.

## 2. Using Random class in Java.

```
Random rand = new Random();
int value = rand.nextInt(50);
```

This will give value from 0 to 49.

For 1 to 50: `rand.nextInt((max - min) + 1) + min;`

Source of some Java Random awesomeness.