如何在特定范围内生成随机int值？
以下方法存在与整数溢出相关的错误：
randomNum = minimum + (int)(Math.random() * maximum);
// Bug: `randomNum` can be bigger than `maximum`.
Random rn = new Random();
int n = maximum - minimum + 1;
int i = rn.nextInt() % n;
randomNum = minimum + i;
// Bug: `randomNum` can be smaller than `minimum`.
当前回答
范围[最小值最大值]（含）内的随机数：
int randomFromMinToMaxInclusive = ThreadLocalRandom.current()
.nextInt(min, max + 1);
其他回答
public static void main(String[] args) {
Random ran = new Random();
int min, max;
Scanner sc = new Scanner(System.in);
System.out.println("Enter min range:");
min = sc.nextInt();
System.out.println("Enter max range:");
max = sc.nextInt();
int num = ran.nextInt(min);
int num1 = ran.nextInt(max);
System.out.println("Random Number between given range is " + num1);
}
Random random = new Random();
int max = 10;
int min = 3;
int randomNum = random.nextInt(max) % (max - min + 1) + min;
我认为这段代码会奏效。请尝试一下：
import java.util.Random;
public final class RandomNumber {
public static final void main(String... aArgs) {
log("Generating 10 random integers in range 1..10.");
int START = 1;
int END = 10;
Random randomGenerator = new Random();
for (int idx=1; idx<=10; ++idx) {
// int randomInt=randomGenerator.nextInt(100);
// log("Generated : " + randomInt);
showRandomInteger(START,END,randomGenerator);
}
log("Done");
}
private static void log(String aMessage) {
System.out.println(aMessage);
}
private static void showRandomInteger(int aStart, int aEnd, Random aRandom) {
if (aStart > aEnd) {
throw new IllegalArgumentException("Start cannot exceed End.");
}
long range = (long)aEnd - (long)aStart + 1;
long fraction = (long) (range * aRandom.nextDouble());
int randomNumber = (int) (fraction + aStart);
log("Generated" + randomNumber);
}
}
使用nexttint（n）方法为最小值和最大值的差值生成一个随机数，然后将最小值添加到结果中：
Random rn = new Random();
int result = rn.nextInt(max - min + 1) + min;
System.out.println(result);
要生成“介于两个数字之间”的随机数，请使用以下代码：
Random r = new Random();
int lowerBound = 1;
int upperBound = 11;
int result = r.nextInt(upperBound-lowerBound) + lowerBound;
这将为您提供一个介于1（含）和11（不含）之间的随机数，因此通过添加1来初始化上限值。例如，如果要生成1到10之间的随机数，则使用11而不是10初始化上限数。
