什么是C ++定义，声明和赋值？ [英] What exactly are C++ definitions, declarations and assignments?

问题描述

我倾向于使用词语define，declare和assign可互换，但这似乎是一些人的犯罪。这是正当的吗？我应该只使用单词declare第一次我分配到一个变量？

I tend to use the words define, declare and assign interchangeably but this seems to cause offense to some people. Is this justified? Should I only use the word declare for the first time I assign to a variable? Or is there more to it than that?

推荐答案

定义和声明是相似的，但赋值是非常不同的。

Define and declare are similar but assign is very different.

这里我声明（或定义）一个变量：

Here I am declaring (or defining) a variable:

int x;

这里我为该变量赋值：

x = 0;

这里我在一个语句中执行：

Here I am doing both in one statement:

int x = 0;

请注意

并非所有语言都支持在一个语句中声明和赋值：

Not all languages support declaration and assignment in one statement:

T-SQL

declare x int;
set x = 0;

有些语言要求在声明时为变量赋值。此要求允许语言的编译器或解释器推断变量的类型：

Some languages require that you assign a value to a variable upon declaration. This requirement allows the compiler or interpreter of the language to infer a type for the variable:

Python

x = 0

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