Java矢量帮助

发布于 2024-09-17 11:11:11 字数 201 浏览 5 评论 0 原文

我刚刚开始Java。请让我知道这个语句的意思

class ABC{
transient Vector<int> temp[];

ABC(int max)
{
 this.temp = new Vector [max];
}

是创建一个大小为 max 的 int 向量吗？

我是 C++ 人。

原文

I have just started the Java. Please let me know what this statement says

class ABC{
transient Vector<int> temp[];

ABC(int max)
{
 this.temp = new Vector [max];
}

Is it creating a vector of int which size is max?

I am C++ person.

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じ违心 2024-09-24 11:11:11

这将创建一个 Vector 对象数组。数组的长度是作为“max”传入的任何长度。

如果您想要单个向量，请省略 []。要编译上述代码，需要进行一些更改。

import java.util.Vector;

class ABC
{
    transient Vector temp[];

    ABC(int max)
    {
        this.temp = new Vector[max];
    }
}

That creates an array of Vector objects. The length of the array is whatever is passed in as "max".

If you want a single Vector, leave off the []'s. A couple of changes are necessary to get the above code to compile.

import java.util.Vector;

class ABC
{
    transient Vector temp[];

    ABC(int max)
    {
        this.temp = new Vector[max];
    }
}

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你另情深 2024-09-24 11:11:11

不，

要创建初始容量最大的向量，您应该

Vector<Integer> v = new Vector (max)

注意两件事：

使用 Integer 而不是 int。在Java中，Integer是对象，而int是原始类型。集合不能使用原始类型，它们使用对象。
v 的容量不限于 max 个元素。如果您插入超过 max 个整数，它就会增长。

但是让 API 页面说话

Vector 类实现了可增长的
对象数组。就像数组一样，它
包含可以的组件
使用整数索引访问。
然而，Vector 的大小可以增长
或根据需要缩小以适应
之后添加和删除项目
矢量已创建。
每个向量都试图通过维护一个
容量和容量增量。这
容量总是至少一样大
作为向量大小；通常是
更大，因为随着组件的添加
到向量，向量的存储
块的大小增加
容量增量。一个应用程序可以
增加向量的容量
在插入大量之前
成分;这减少了
增量重新分配。

No,

To create a Vector of initial capacity max you should

Vector<Integer> v = new Vector (max)

Note two things:

Usage of Integer and not int. In Java, Integer is an object, while int is a primitive type. Collections can't use primitive types, they use objects.
The capacity of the v is not limited to max elements. It will grow if you insert more than max Integers.

But let the API page do the talking

The Vector class implements a growable
array of objects. Like an array, it
contains components that can be
accessed using an integer index.
However, the size of a Vector can grow
or shrink as needed to accommodate
adding and removing items after the
Vector has been created.
Each vector tries to optimize storage management by maintaining a
capacity and a capacityIncrement. The
capacity is always at least as large
as the vector size; it is usually
larger because as components are added
to the vector, the vector's storage
increases in chunks the size of
capacityIncrement. An application can
increase the capacity of a vector
before inserting a large number of
components; this reduces the amount of
incremental reallocation.