Question

Consider the following code segment, which is intended to assign to num a random integer value between min and max, inclusive. Assume that min and max are integer variables and that the value of max is greater than the value of min. double rn = Math.random(); int num = /* missing code */; Which of the following could be used to replace /* missing code */ so that the code segment works as intended?

Answer 1

To generate a random integer between `min` and `max`, inclusive, you can use the following formula:

```java
int num = min + (int)(rn * (max - min + 1));
```

Here’s how it works:
1. `Math.random()` generates a double between 0.0 (inclusive) and 1.0 (exclusive).
2. Multiplying it by `(max - min + 1)` scales it to be in the range of 0 to `(max - min + 1)` (exclusive).
3. When you cast this result to an integer, it effectively gives you a value in the range `[0, max - min]`.
4. Finally, adding `min` shifts this range up to `[min, max]`.

So the complete line to replace the `/* missing code */` would be:

```java
int num = min + (int)(rn * (max - min + 1));
```

This ensures that `num` is uniformly distributed over the integers from `min` to `max`, including both endpoints.