数组和指针的区别 [英] Difference between array and pointer

问题描述

昨天我用自制的strcpy的功能有点麻烦。现在它虽然，但我有点糊涂了！

 的char * A =你好，世界！ //作品
焦B〔=]你好，世界！ //也适用的strcpy（一，你好！）; //分段故障
的strcpy（二，哈哈!!）; //作品..
 

在哪里是区别？为什么字符指针导致段错误？

为什么这甚至工作？

 的char * A =哈哈; //作品
A =LOL //作品..
 

解决方案

 的char * A =你好，世界！
 

为您提供了一个指向一个字符串。字符串文字可以在只读存储器存在，因此其内容不能改变。

 的char * A =哈哈; //作品
A =LOL //作品..
 

改变指针 A 来指向不同的字符串。它不试图修改任何字符串的内容，所以是安全的/正确的。

 字符B〔=]你好，世界！
 

声明在堆栈上的数组和一个字符串的内容初始化它。栈内存是可写的所以它的万无一失改变这种存储器的内容。

Yesterday I had a little trouble with a homemade "strcpy" function. It works now though but I'm a little confused!

char* a = "Hello, World!"; //Works
char b[] = "Hello, World!"; //Works also

strcpy(a, "Hello!"); //Segmentation fault
strcpy(b, "Haha!!"); //Works..

Where is the difference? Why does the char pointer cause a "Segmentation fault"?

Why does this even work? :

char* a = "Haha"; //works
a = "LOL"; //works..

解决方案

char* a = "Hello, World!";

gives you a pointer to a string literal. A string literal may exist in read only memory so its contents cannot be changed.

char* a = "Haha"; //works
a = "LOL"; //works..

changes the pointer a to point to a different string literal. It doesn't attempt to modify the contents of either string literal so is safe/correct.

char b[] = "Hello, World!"

declares an array on the stack and initialises it with the contents of a string literal. Stack memory is writeable so its perfectly safe to change the contents of this memory.

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