动态内存分配指向结构的指针数组 [英] dynamic memory allocation of an array of pointers to structures

问题描述

我一直在尝试为动态分配一系列指向结构的指针。因为它没有工作，我试图尽可能地减少问题。这就是我所拥有的：

Hi,

I''ve been trying to allocate dynamicaly an array of pointers to structures. As it didn''t work, I tried to reduce the problem as much as possible. This is what I have :

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推荐答案

我一直在尝试为动态分配一系列指向结构的指针。因为它没有工作，我试图尽可能地减少问题。这就是我所拥有的：

Hi,

I''ve been trying to allocate dynamicaly an array of pointers to structures. As it didn''t work, I tried to reduce the problem as much as possible. This is what I have :

展开 | 选择 | Wrap | 行号

p [ i]不再是地址了...... p [i]是数组的元素而不是指向元素的指针所以你不能使用 - >。你如何使用calloc为2个大小为struct_p的对象的数组分配内存，所以应该没问题。我认为如果你用''替换'' - >''就行了。''

问候

p[i] is no more an adress...p[i] is an element of an array and not a pointer to an element so you can''t use ->. How you use calloc you allocate memory for an array of 2 objects of size of struct_p, so that should be fine. I think it should work if you replace ''->'' by ''.''
Regards

谢谢你的支持回答。


我使用sizeof（struct_p *）而不是sizeof（struct_p）。它有什么区别吗？我认为，这样，数组的元素就是指针。


问候

Thank you for your answer.

I used sizeof(struct_p *) and not sizeof(struct_p). Does''nt it make any difference? I thought that, this way, the elements of the array would be pointers.

Regards

感谢您的回答。


我使用sizeof（struct_p *）而不是sizeof（struct_p）。它有什么区别吗？我想，这样，数组的元素就是指针。


问候

Thank you for your answer.

I used sizeof(struct_p *) and not sizeof(struct_p). Does''nt it make any difference? I thought that, this way, the elements of the array would be pointers.

Regards

其实我不是''知道运算符sizeof，但从我的理解sizeof没有定义任何类型（即指针或变量）只是给出八位字节的大小。考虑到这一点你应该使用sizeof（struct_p），因为你想要为p分配内存，以便它可以容纳两个struct_p类型的对象。

使用sizeof（struct_p *）意味着p可以容纳2个对象指向struct_p的指针大小。

我不确定这个，但我认为就是这样。


你还得错吗使用''。''而不是'' - >''？

Actually I don''t know well the operator sizeof, but from what I understand sizeof doesn''t define any type (i.e. pointer or variable) just giving the size in octets. Considering this you should use sizeof(struct_p), because you want allocate memory to p so that it can hold two objects of type struct_p.
Using sizeof(struct_p *) it means that p can hold 2 objects of size of a pointer to struct_p.
I''m not sure about this, but I think it is this way.

Did you still get errors using the ''.'' instead of the ''->'' ?

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