C-函数返回2D数组 [英] C - Function return 2D array

问题描述

也许我的问题很简单，但是我是C语言的新人.

Maybe my question is easy but I am newby in C.

我创建了一个函数，该函数从文件中读取一些数据，然后将其传递给另一个函数，该函数解析给定行数和列数并创建2D数组.

I create a function which read some data from a file and then pass them to a another function which parse them given number of rows and columns and create a 2D array.

我想返回此数组以便在其行中执行一些操作.如何在C中返回2D数组

I want to return this array in order to perform some operantions in its rows. How can I return a 2D array in C

有人可以给我一个例子吗，或者我做错了什么?

Can someone give me an example or what may I did wrong?

致谢

推荐答案

请注意，用C返回数组是初学者的陷阱，因为它高度依赖于存储时间:

Beware, returning arrays in C is a beginner's trap, because it is highly dependant on the storage duration:

• 静态或全局:没问题，但是下次调用会覆盖内容
• 自动:从不这样做！实际上返回的是一个悬挂指针，因为数组的寿命在return语句的结尾处结束
• dynamic(malloc-ed):很好，但是调用方必须稍后将其释放.

• static or global: no problem, but content will be overwritten by next call
• automatic : never do that! What is actually returned is a dangling pointer, because the array's life ends at the end of the return statement
• dynamic (malloc-ed): fine, but caller must free it later.

一种更惯用的方法是，调用方传递它拥有的数组及其大小.

An more idiomatic way is that the caller passes an array that it owns, along with its size(s).

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