C++ 字符数组 *
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Array of char *
提问by user353060
I am having problems with array pointers. I've looked through Google and my attempts are futile so far.
我在使用数组指针时遇到问题。我已经浏览过谷歌，到目前为止我的尝试都是徒劳的。
What I would like to do is, I have a char name[256]. I will be 10 of those. Hence, I would need to keep track of each of them by pointers.
我想做的是，我有一个字符名称[256]。我将是其中的 10 个。因此，我需要通过指针跟踪它们中的每一个。
Trying to create a pointer to them.
试图创建一个指向它们的指针。
int main()
{
char superman[256] = "superman";
char batman[256] = "batman";
char catman[256] = "catman";
char *names[10];
names[0] = superman;
names[1] = batman;
system("pause");
return 0;
}
How do I actually traverse an array of pointers?
我如何实际遍历指针数组？
回答by nos
names[0] is a char* to whatever you stored in names[0] (which in this case is a pointer to the first element in your supermanarray) thus your guess at e.g cout << names[0] << endl;is correct.
names[0] 是您存储在 names[0] 中的任何内容的 char*（在这种情况下，它是指向superman数组中第一个元素的指针），因此您对 eg 的猜测cout << names[0] << endl;是正确的。
If you want to traverse that array, you need to know when to stop so you're not traversing pointers you havn't yet initialized- if you knowyou have initialized 2 of those pointers, you could do e.g.
如果你想遍历那个数组，你需要知道什么时候停止，这样你就不会遍历你还没有初始化的指针——如果你知道你已经初始化了其中的 2 个指针，你可以这样做
for(int i = 0; i < 2 ; i++) {
std::cout << names[i] << std::endl;
}
As an alternative, place a NULL pointer after the last element you have initialized(make sure there's room for that NULL pointer) e.g.
作为替代方案，在您初始化的最后一个元素之后放置一个 NULL 指针（确保该 NULL 指针有空间）例如
names[2] = NULL;
for(int i = 0; names[i] != NULL ; i++) {
std::cout << names[i] << std::endl;
}
回答by OlimilOops
why not use strings and a Vector of strings to store the names? smpl:
为什么不使用字符串和字符串向量来存储名称？标准：
#include <string>
#include <iostream>
#include <Vector>
//using namespace std;
int main(void) {
std::string superman = "superman";
std::string batman = "batman";
std::vector<std::string> names;
names.push_back(superman);
names.push_back(batman);
for (unsigned int i = 0; i < names.size(); ++i) {
std::cout << names[i] << std::endl;
}
char c; std::cin >> c;
}
回答by smcameron
char *names[] = { "superman", "batman", "whatever", NULL };
...
...
for (int i = 0; names[i] != NULL; i++)
printf("%s\n", names[i]);
He might not want to use a vector because he might be using C, not C++.
他可能不想使用向量，因为他可能使用的是 C，而不是 C++。
edit: I see he tagged it C++ though.
编辑：我看到他把它标记为 C++。
回答by Mike
Using arbitrary fixed length arrays to manipulate strings is a complete no no. In my company, this code would be illegal, period. This practice is exactly the cause of most security breaches and it's what makes C/C++ (that uses this type of code) notoriously unsecure. I highly recommend the C++ solution from "Oops".
使用任意固定长度的数组来操作字符串是完全不可以的。在我的公司，这段代码是非法的，句号。这种做法正是大多数安全漏洞的原因，也是导致 C/C++（使用这种类型的代码）非常不安全的原因。我强烈推荐来自“Oops”的 C++ 解决方案。
回答by Thomas Matthews
First try using std::string, this will relieve you of memory allocation and deallocation issues.
Second, use std::vector<string>which dynamically expands as needed.
首先尝试使用std::string，这将减轻您的内存分配和释放问题。
其次，std::vector<string>根据需要使用which 动态扩展。
If you mustuse char *, you will need an array of pointers to char *.
This is declared as:
如果必须使用char *，则需要一个指向 的指针数组char *。
这被声明为：
char * array_of_C_strings[10]; // Define an array of 10 pointers to char *.
char * array_of_C_strings[10]; // 定义一个包含 10 个指向 char * 的指针的数组。
If the strings are fixed length:
如果字符串是固定长度的：
char array_of_fixed_length_C_strings[10][256]; // Array of 10 C-Strings that are max. size 256.
char array_of_fixed_length_C_strings[10][256]; // 最多 10 个 C 字符串的数组。尺寸 256。
Assignment:
任务：
char hello[32];
strcpy(hello, "Hello");
array_of_C_Strings[0] = hello; // Note: only pointers are copied
strcpy(array_of_fixed_length_C_Strings[2], hello); // Copy actual content of string.
With std::stringand std::vector<std::string>:
随着std::string和std::vector<std::string>：
std::string hello = "hello";
std::vector<std::string> string_container;
string_container.push_back(hello);
string_container.push_back("world!");
std::cout << string_container[0]
<< ' '
<< string_container[1]
<< "\n";
The example using std::stringand std::vectorlooks simpler than an array of char *, but that is my opinion, YMMV.
使用std::string和的示例std::vector看起来比 的数组简单char *，但这是我的观点，YMMV。
