（Math.random（）* a）;可能有损转换从double到int [英] (Math.random() * a); possible lossy conversion from double to int

问题描述

在int x =（Math.random（）* a）行下面的代码中，我收到一条错误，上面写着不兼容的类型：可能有损转换从double转换为int在* a）;

In the code bellow on the line "int x = (Math.random() * a)" I get a error that says "incompatible types: possible lossy conversion from double to int" at "* a);"

`
import java.util.Scanner;
public class problem4 {
    public static void rollDice() {
        Scanner reader = new Scanner(System.in);
        System.out.println("How many random numbers should be generated?");
        int n = reader.nextInt();
        Scanner reader1 = new Scanner(System.in);
        System.out.println("What is the number of values for each random draw?");
        int a = reader.nextInt();
        for (int i = 0; i <= n; i++) {
            int x = (Math.random()* a);
            System.out.println("Random number "+i+" is "+x+".");
}}}`

我在BlueJ中使用Java。

I am using Java in BlueJ.

推荐答案

Math.random 返回 double 。然后尝试将该双倍乘以 a 并将其放入 int 。

Math.random returns a double. Then you try to multiply that double by a and put it into an int.

int 总是一个整数（没有小数位）。所以它通过执行该操作（将其放回 int ）告诉您正在丢失这些小数位。

An int is always a whole number (no decimal places). So it's telling you that you're losing those decimal places by doing that operation (putting it back into an int).

您可以通过使 x a double 。或者，如果您确实需要整数，则可以通过执行以下操作将 x 的值显式转换为 int ：
int x =（int）（Math.random（）* a）

You could fix the problem by making x a double. Or if you actually want the whole numbers, you can explicitly cast the value of x to an int by doing: int x = (int) (Math.random() * a)

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