Constants provide stability and prevent accidental data modification by representing values that never change.
Word in 30 Seconds
- A value that remains fixed during a process or calculation.
- Commonly used in mathematics and computer programming to ensure stability.
- The direct opposite of a variable, which can change values.
Overview
- 1概述：在科学研究和工程开发中，常量（Constant）是一个核心概念。它代表了一个确定的、不可更改的数值或属性。在计算机科学中，常量一旦被定义并赋值，其存储的数据在整个程序生命周期内都不能被修改。2) 使用模式：在编程中，常量通常通过特定的关键字（如 const, final, static）来声明。它们常被用于定义全局配置（如数据库连接字符串）、数学常数（如圆周率）或业务逻辑中的固定限制（如最大重试次数）。3) 常见语境：常量广泛应用于数学公式、物理定律（如普朗克常量）、计算机编程以及经济模型中。4) 近义词比较：‘常量’与‘常数’在数学中经常通用，但在计算机领域，‘常量’更强调其在内存中不可变的特性；而‘固定值’则是一个更通俗的说法，缺乏技术严谨性。与之相反的词是‘变量’，变量的值是可以根据逻辑流转而发生改变的。
Examples
我们需要在程序的开头定义一些全局常量。
technicalWe need to define some global constants at the beginning of the program.
在这个数学模型中，引力被设为一个常量。
academicIn this mathematical model, gravity is set as a constant.
生活中唯一的常量就是变化本身。
informalThe only constant in life is change itself.
该实验要求保持环境温度为一个常量。
formalThe experiment requires keeping the ambient temperature as a constant.
Common Collocations
Common Phrases
命名常量
Named constant
布尔常量
Boolean constant
字符串常量
String constant
Often Confused With
A variable is a storage location that can hold different values over time, while a constant's value is fixed.
While often used interchangeably, '常数' (constant number) usually refers to a fixed numerical value in math, whereas '常量' is a broader term in computing.
Grammar Patterns
How to Use It
Usage Notes
The term is predominantly used in formal, technical, and academic contexts. In daily conversation, it might be used metaphorically to describe something that never changes. It is a neutral term with no specific emotional coloring.
Common Mistakes
A common mistake is using '常量' when you actually mean 'constant' as an adjective (e.g., 'constant rain'). In Chinese, '常量' is strictly a noun; the adjective form would be '持续的' or '不断的'.
Tips
Use descriptive names for your constants
Instead of using '3.14', define a constant named 'PI' to make your logic clearer to others.
Avoid hardcoding values in your logic
Hardcoding magic numbers makes code brittle; always replace them with named constants for better maintenance.
Universal standards in software engineering
The concept of 'constants' is universal across all programming languages, following similar naming conventions globally.
Word Origin
Derived from the combination of '常' (enduring/regular) and '量' (measure/quantity), reflecting the concept of an unchanging measurement in scientific logic.
Cultural Context
In the Chinese tech industry, English terms are often mixed, but '常量' remains the standard translation for 'constant' in all localized documentation and textbooks.
Memory Tip
'常' (cháng) means 'always' or 'constant', and '量' (liàng) means 'amount' or 'quantity'. Together, it literally means 'the amount that is always the same'.
Frequently Asked Questions
4 questions常量的值在定义后不可更改，而变量的值可以根据程序运行的需要随时被重新赋值。
使用常量可以提高代码的可读性，防止意外修改重要数据，并使得全局参数的维护更加方便。
在大多数编程规范中，常量通常使用全大写字母命名，并用下划线分隔单词，例如：MAX_SPEED。
最著名的数学常量包括圆周率 (π ≈ 3.14159) 和自然对数的底数 (e ≈ 2.71828)。
Test Yourself
在编写代码时，如果一个数值在运行过程中永远不会改变，我们应该把它定义为___。
常量（Constant）的定义就是其值在运行过程中保持不变的量。
下列哪项数据在程序中最适合被声明为常量？
一周的天数是固定不变的自然属性，非常适合作为常量；其他选项都会随时间或状态改变。
请用“常量”一词描述物理学中的光速。
光速在物理学中是一个恒定的基本常数。
Score: /3
Summary
Constants provide stability and prevent accidental data modification by representing values that never change.
- A value that remains fixed during a process or calculation.
- Commonly used in mathematics and computer programming to ensure stability.
- The direct opposite of a variable, which can change values.
Use descriptive names for your constants
Instead of using '3.14', define a constant named 'PI' to make your logic clearer to others.
Avoid hardcoding values in your logic
Hardcoding magic numbers makes code brittle; always replace them with named constants for better maintenance.
Universal standards in software engineering
The concept of 'constants' is universal across all programming languages, following similar naming conventions globally.
Examples
4 of 4我们需要在程序的开头定义一些全局常量。
We need to define some global constants at the beginning of the program.
在这个数学模型中，引力被设为一个常量。
In this mathematical model, gravity is set as a constant.
生活中唯一的常量就是变化本身。
The only constant in life is change itself.
该实验要求保持环境温度为一个常量。
The experiment requires keeping the ambient temperature as a constant.
Related Content
This Word in Other Languages
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缺席
B1The state of being absent from a place or event where one is expected to be, such as a class, meeting, or ceremony.
抽象的
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抽象地
B1In an abstract manner; conceptually.
艰深
B1Profound; abstruse; recondite.
学术性
A2Academic; scholarly; relating to education and scholarship.
学术化
B1Academic; characterized by formal study or research.
学术会议
A2Academic conference; a formal meeting for academic discussions.
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B1Exchange of ideas, information, and research among scholars.
学术期刊
B1A periodical publication containing scholarly articles.
教务处
A2Academic affairs office; department handling educational administration.
