如何让我的代码选择从X到Y的数字？ [英] How do I make my code choose a number from X to Y?
问题描述
import java.util.Random;
import java.lang.Math;
public class Exercise_7_8e {
public static void main（String [] args）{
// TODO自动生成方法存根
float [] Array1 = new float [99];
float max = Array1 [0];
float min = Array1 [0];
for（int i = 0; i< Array1.length; i ++）{
Array1 [i] =（int）（Math.random（）* 200 + 6）;
if（Array1 [i]> max）{
max = Array1 [i];
}否则if（Array1 [i]< min）
min = Array1 [i];
}
System.out.println（最大值是+最大值）;
System.out.println（最小值是+ min;
}
}
输出：
最大值是205.0
最小值是0.0
我尝试过：
所以Math.random（）的格式化应该是Math.random（）* max + min正确吗？但是，在我的代码中，输出将始终返回0作为min。我如何解决这个问题？
import java.util.Random;
import java.lang.Math;
public class Exercise_7_8e {
public static void main(String[] args) {
// TODO Auto-generated method stub
float[] Array1 = new float[99];
float max = Array1[0];
float min = Array1[0];
for (int i = 0; i < Array1.length; i++) {
Array1[i] = (int) (Math.random() * 200 + 6);
if (Array1[i] > max) {
max = Array1[i];
} else if (Array1[i] < min)
min = Array1[i];
}
System.out.println("The largest value is " + max);
System.out.println("the smallest value is " + min);
}
}
Output:
The largest valus is 205.0
the smallest value is 0.0
What I have tried:
So the formatting of Math.random() is supposedly Math.random()*max + min correct? However, in my code the output will always return 0 as the min. How do i fix this?
推荐答案
float[] Array1 = new float[99];<br />
float min = Array1[0];
从未初始化的数组中分配 min 。到目前为止，我知道Java它默认初始化为'0'。我的个人观点：总是明确地初始化变量而不依赖于编译器/链接器行为。
所以 Math.random（）* 200 + 6 永远不会< min意味着< 0（来自默认初始化）。
尝试 - 并考虑它的含义：
float min = 9999999.9 或者更好的max（浮动）如果它确实存在于Java中（我认为它是Float.MAX_VALUE）
我希望它帮助。
You assign min from a not initialiezed Array. So far I know Java it does initialize by Default to '0'. My personal opinion: Always initialize variables explicitely and don't rely on Compiler/Linker behaviours.
So Math.random() * 200 + 6 will never be < min which means < 0 (from the Default init).
Try - and think about what it means:
float min = 9999999.9 or much better to max(float) if it does exists in Java (I think it is Float.MAX_VALUE)
I hope it helps.
因此Math.random（）的格式化应该是Math.random（ ）* max + min是否正确？
So the formatting of Math.random() is supposedly Math.random()*max + min correct?
简单阅读文档分析会告诉你答案。
A simple reading of documentation an analyze would tell you the answer.
0 <= Math.random() < 1
0 <= Math.random() * 200 < 200
6 <= Math.random() * 200 + 6 < 206
6 <= (int) (Math.random() * 200 + 6) < 206
6 <= (int) (Math.random() * 200 + 6) <= 205
但是，在我的代码中，输出将始终返回0作为min。我如何解决这个问题？
However, in my code the output will always return 0 as the min. How do i fix this?
问题是你初始化 min 0，这已经低于你的任何随机值得到。
请注意，您不需要将每个随机值存储在数组中，因为您不会重复使用它们。
The problem is that you initialize min with 0 which is already lower than any random value that you get.
Note that you don't need to store each random values in an array because you don't reuse them.
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