结构指针和自指针 [英] pointer to structure and self pointers

问题描述

结构中的自引用指针和结构指针之间有什么区别?

    struct abc
    {
    int data;
    struct abc *next;
    }
    struct abc *pt;

1. *next和*pt ??

有什么区别

2. 它们的用法有何不同??

我真的怀疑这两者之间

我是初学者

第一个示例主要用于链接列表

结构节点的指针和自引用指针是否相同?

请参阅

see-programming.blogspot.in/2013/05/chain-hashing-separate-chaining-with.html在这里，我们使用结构哈希* hashTable作为数组..how?我们可以用* pt

做同样的事情吗

解决方案

1. 它们是同一类型.它们的行为完全相同.

   一些用法示例:

   // declare 2 structs
   struct abc s1;
   struct abc s2;
   
   // point pt to s1
   pt = &s1;
   
   // point s1.next to s2
   s1.next = &s2;
   
   // access pt->data
   int a = pt->data;
   
   // access s1.next->data
   int a = s1.next->data;
   

2. 用法上的差异:

   • 只有一个pt变量.

   • 对于每个struct abc变量，都有一个next变量.

   在链接列表的上下文中，只有一个头指针，因此将是pt.
   但是每个节点都指向下一个节点，因此应使用next.

3. 使用指针作为数组吗?

   是的，可以使用pt或next完成.

   指针仅指向内存中的地址.在该位置可以有任意数量的结构.

   如果要使用它作为数组(或通常只使用指针)，则只需确保不尝试访问未为其分配内存的元素(例如，使用malloc )，并在使用后释放内存(如果您使用的是malloc).

   一些使用数组的示例:

   // declare a struct
   struct abc s1;
   
   // make an array of size 10
   struct abc *a1 = malloc(10*sizeof(struct abc));
   
   // give the 4th element a new value
   a1[4] = s1;
   
   // free the memory
   free(a1);
   

我希望能有所帮助.

What is the difference between self referential pointer in structure and pointer to structure?

    struct abc
    {
    int data;
    struct abc *next;
    }
    struct abc *pt;

1. What are the differences between *next and *pt??

2. How they differ in their use??

I am really in doubt between these two

I am a beginner

First example is used mainly for linked list

Are pointer to structure node and self referential pointer the same thing?

please see

see-programming.blogspot.in/2013/05/chain-hashing-separate-chaining-with.html here we have used struct hash *hashTable as an array ..how?? and can we do same with *pt

解决方案

1. They are of the same type. They behave in the exact same way.

   Some example usage:

   // declare 2 structs
   struct abc s1;
   struct abc s2;
   
   // point pt to s1
   pt = &s1;
   
   // point s1.next to s2
   s1.next = &s2;
   
   // access pt->data
   int a = pt->data;
   
   // access s1.next->data
   int a = s1.next->data;
   

2. Differences in usage:

   • There's only one pt variable.

   • For every struct abc variable, there is a next variable.

   In the context of a linked-list, there is only one head pointer, thus pt would be it.
   But each node points to the next node, thus next should be used for this.

3. Using pointers as arrays?

   Yes, this can be done with either pt or next.

   A pointer just points to an address in memory. There can be any number of structs following on each other at that location.

   If you want to use it as an array (or just using pointers in general), you just have to make sure you don't try to access elements that you didn't allocate memory for (with malloc for example) and free the memory after usage (if you used malloc).

   Some example usage with array:

   // declare a struct
   struct abc s1;
   
   // make an array of size 10
   struct abc *a1 = malloc(10*sizeof(struct abc));
   
   // give the 4th element a new value
   a1[4] = s1;
   
   // free the memory
   free(a1);
   

I hope that helps a bit.

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