在 C 中将文本存储在字符矩阵中

发布于 2024-11-30 13:25:51 字数 638 浏览 0 评论 0原文

我想从标准输入中获取文本并将其存储到字符串数组中。但我希望字符串数组在内存中是动态的。我现在的代码如下：

char** readStandard()
{
  int size = 0;
  char** textMatrix = (char**)malloc(size);
  int index = 0;
  char* currentString = (char*)malloc(10); //10 is the maximum char per string
  while(fgets(currentString, 10, stdin) > 0)
    {
      size += 10;
      textMatrix = (char**)realloc(textMatrix, size);
      textMatrix[index] = currentString;
      index++;
    }
  return textMatrix;
}

打印时得到的结果是在数组的所有位置中读取的最后一个字符串。

例子阅读：你好好的到见面您

打印：你你你你你

为什么？我在互联网上搜索过。但我没有发现这种错误。

原文

I want to take a text from the standard input and store it into an array of strings. But I want the array of strings to be dynamic in memory. My code right now is the following:

char** readStandard()
{
  int size = 0;
  char** textMatrix = (char**)malloc(size);
  int index = 0;
  char* currentString = (char*)malloc(10); //10 is the maximum char per string
  while(fgets(currentString, 10, stdin) > 0)
    {
      size += 10;
      textMatrix = (char**)realloc(textMatrix, size);
      textMatrix[index] = currentString;
      index++;
    }
  return textMatrix;
}

The result I have while printing is the last string read in all positions of the array.

Example
Reading:
hello
nice
to
meet
you

Printing:
you
you
you
you
you

Why? I've searched over the Internet. But I didn't find this kind of error.

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绝對不後悔。 2024-12-07 13:25:51

您一遍又一遍地存储相同的地址 (currentString)。尝试类似的

while(fgets(currentString, 10, stdin) > 0)
{
     textMatrix[index] = strdup(currentString); /* Make copy, assign that. */
}

函数 strdup 不是标准的（只是广泛可用）。使用 malloc + memcpy 自己实现应该很容易。

You are storing the same address (currentString) over and over. Try something like

while(fgets(currentString, 10, stdin) > 0)
{
     textMatrix[index] = strdup(currentString); /* Make copy, assign that. */
}

The function strdup is not standard (just widely available). It should be easy to implement it yourself with malloc + memcpy.

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请恋爱 2024-12-07 13:25:51

currentString 始终指向同一个内存区域，并且 textMatrix 中的所有指针都将指向它

char** readStandard()
{
  int size = 0;
  char** textMatrix = (char**)malloc(size);
  int index = 0;
  char currentString[10];
  while(fgets(currentString, 10, stdin) > 0)
    {
      size += sizeof(char*);
      textMatrix = (char**)realloc(textMatrix, size);
      textMatrix[index] = strdup(currentString);
      index++;
    }
  return textMatrix;
}

currentString always point to the same memory area and all the pointers in textMatrix will point to it

char** readStandard()
{
  int size = 0;
  char** textMatrix = (char**)malloc(size);
  int index = 0;
  char currentString[10];
  while(fgets(currentString, 10, stdin) > 0)
    {
      size += sizeof(char*);
      textMatrix = (char**)realloc(textMatrix, size);
      textMatrix[index] = strdup(currentString);
      index++;
    }
  return textMatrix;
}

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