制作一个数组来保存字符数组的数组用C [英] Making an Array to Hold Arrays of Character Arrays in C
问题描述
我的C比此刻生锈的多一点，所以我没有创造的东西，我认为应该是pretty基础。
My C is a little more than rusty at the moment, so I'm failing to create something I think should be pretty basic.
请允许我引用字符数组作为这篇文章的字符串。这将使事情为我和你更清晰。
Allow me to refer to character arrays as strings for this post. It will make things clearer for both me and you.
我有什么是可以容纳1个或多个字符串数组。例如{AB，CD，EF}。我不想再拍数组来存储字符串数组的多个版本。因此，像{{AB，CD，EF}，{GH，IJ}，{KL}}
What I have is an array that can hold 1 or more strings. For instance {"ab", "cd", "ef"}. I want to make another array to store multiple versions of the array of strings. So something like {{"ab", "cd", "ef"}, {"gh", "ij"}, {"kl"}}.
我现在所拥有的是：
char *arrayOfStrings[50]; // a single array to hold multiple strings
char **arrayOfArraysOfStrings[10]; // array to hold multiple snapshots of arrayOfStrings
随着时间的字符串的变化和我使用的字符串数组的数组基本上持有arrayOfStrings的历史快照的阵列。当我需要访问数据快照阵列我的问题就来了。这是code我必须把东西到快照数组：
The array of strings changes over time and I'm using the array of arrays of strings to basically hold historical snapshots of arrayOfStrings. My problem comes when I need to access the snapshot array for data. This is the code I have to put stuff into the snapshot array:
arrayOfArraysOfStrings[input_index] = arrayOfStrings; // you can assume input_index is updated correctly, I've already checked that.
这似乎是不正确的，因为当我尝试访问并打印出快照数组的内容，只打印出从最近arrayOfStrings的信息。我会与此的想法是，让他们放置arrayOfChars在快照阵列的条目指向，所以我以后可以访问它的地址。
This appears to be incorrect since when I try to access and print out the contents of the snapshot array, it only prints out the information from the most recent arrayOfStrings. The idea I was going for with this was to store the address of where arrayOfChars is pointing in an entry of the snapshot array so I can access it later.
目前，对快照的访问数组中的一个条目来完成这样的：
Right now, access to an entry in the snapshot array is accomplished like this:
arrayOfArraysOfChars[historicalIndex][indexOfTargetChar]
有我期待回答几个问题：
There are several questions I'm looking to answer:
- 是我列出适合什么，我试图做或方法有一个缺陷在我的整个逻辑？
- 我在做什么毛病我目前的code，我如何解决这个问题？
- 有没有更好的方式来做到这一点，如果是的话，请问该数组初始化，除了阵列，并从阵列工作在看什么？
- 编辑4 / 18--
问题的部分原因是，我设置的指针在arrayOfArraysOfStrings为指向arrayOfStrings指向同样的事情。既然arrayOfStrings被编辑过的不好。我需要一些方法简单地分配一个新的内存块arrayOfStrings在指向复制一个二维数组... preferably。
--edit 4/18-- Part of the problem is that I'm setting pointers in arrayOfArraysOfStrings to point to the same thing that arrayOfStrings is pointing to. That's bad since arrayOfStrings gets edited. I need some way to duplicate a 2D array... Preferably by simply allocating a new block of memory for arrayOfStrings to point at.
推荐答案
您必须在这两个的阵列中的一个太很多三分球。
You have one-too-many pointers in both of your arrays.
char arrayOfChars[50]; // a single array of characters
char *arrayOfArraysOfChars[10]; // array to hold multiple single arrays of characters
由于正在使用像一个缓冲arrayOfChars（新的数据总是会去那里第一），你需要将字符串的副本保存到arrayOfArrays。 POSIX的功能的strdup 应有助于在这里。
通知＆安培; 和 * 是对立的，所以＆放大器; * 和 *放大器; 什么都不做。
Notice & and * are opposites, so &* and *& do absolutely nothing.
您也可以，使arrayOfArrays字面上说。
You could also, make the arrayOfArrays literally that.
char arrayOfChars[50]; // a single array of characters
char arrayOfArraysOfChars[10][50]; // array to hold multiple single arrays of characters
通过这种设置，你应该使用的strcpy 将数据复制到arrayOfArrays。
With this setup, you should use strcpy to copy the data into arrayOfArrays.
看了你的编辑，我认为你需要开始的真正的简单。和FWIW变量名是一种错误的匈牙利的。
Having read your edit, I think you need to start real simple. And FWIW the variable names are the wrong kind of Hungarian.
对于我认为你想要做什么，我只是一个单一的字符数组开始。这将是正在输入，并检查了主要的缓存的，持有的字符串。
For what I think you're trying to do, I'd start with just a single char array. This will be the main buffer, to hold strings that are being input and examined.
enum { BUFSZ = 50 };
char buf[BUFSZ + 1];
然后你可以用与fgets 或任何使用它。
fgets(buf, BUFSZ, infile);
要起来数组保存这些，我会使用的strdup 其自动修整。如果字符串将是大多是2个字符长，我不想被用于每一个48额外的字节。所以，char指针（字符串）数组。
To save these up in an array, I'd use strdup for its automatic trimming. If the strings are going to be mostly 2 characters long, I don't want 48 extra bytes being used for each one. So, an array of char pointers (strings).
enum { STRVSZ = 40 };
char *strv[STRVSZ + 1];
int i;
i = 0;
strv[i] = strdup(buf);
strv[i+1] = NULL; // This makes it an "argv-style" NULL-terminated array of strings
++i; // i is now the index of the next element, and a count of elements already added
STRV 的每个元素都是一个字符指针。但要preserve我们的理智，我们正在努力的抽象掉的一些细节分心了一会儿，并且治疗的字符串的作为一个单独的数据类型。
Each element of strv is a char pointer. But to preserve our sanity, we're trying to abstract away some of that distracting detail for a moment, and treat strings as a separate data type.
现在创建的这些名单，我们再次做同样的事情。但是，没有任何的strdup 型功能，使指针数组的副本，所以我们要分开的分配和复制。
Now to create lists of these, we do the same thing again. But there's no strdup-type function to make a duplicate of an array of pointers, so we have to separate the allocation and copying.
enum { STRVVSZ = 20 };
char **strvv[STRVVSZ + 1];
int j;
j = 0;
strvv[j] = calloc(i+1, sizeof *strvv[j]); // assuming i is the count of elements
memcpy(strvv[j], strv, i * sizeof *strvv[j]);
++j; // j is now the index of the next string-pointer array in the array-of-same,
// and a count of elements already added.
现在，我的名字是一样的你傻傻的，但他们更短的！
Now, my names are just as silly as yours, but they're shorter!
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