如何在uninitiliazed变量得到一个垃圾的价值？ [英] How does an uninitiliazed variable get a garbage value?

问题描述

当我们创建一个变量，并且不将其初始化，然后叫了一些（随机）数的垃圾值的被分配给它。

When we create a variable and don't initialize it, then some (random) number called garbage value is assigned to it.

• 此值如何分配给变量？


• 什么是整体的概念/这背后的机制呢？


• 这是否只发生在C 3

推荐答案

垃圾值不是的分配的，而该值已经存在。当你分配你保留的一块内存变量 - 直到你覆盖它内存将包含一切随机的信息在那里之前

The garbage value is not assigned, rather the value is already there. When you allocate a variable you are reserving a piece of memory - until you overwrite it that memory will contain whatever "random" information was there before.

作为一个比喻，认为分配就像买一块土地的变量 - 直到你用它做什么（比如盖房子）土地就只能任何垃圾已经坐在那里（像一个老摇摇欲坠的房子）。

As a metaphor, think of allocating a variable like buying a piece of land - until you do something with it (like build a house) the land will just have whatever trash was already sitting there (like an old crumbling house).

有些语言会自动用零填充新分配的变量 - 这需要时间做。在更多的做自己动手的语言，如C这种额外behavoir没有保证的广告（尽管在某些系统上的内存，无论是语言的清除，例如，作为一种安全措施）

Some languages will automatically fill newly allocated variables with zeros - this takes time to do. In more "do-it-yourself" languages like C this extra behavoir is not guarenteed (though on some systems memory is cleared regardless of language, for example as a security measure)

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