C语言读取ASCII图像文本到二维数组异常问题及解决

我尝试将名为"ascii_image.txt"的ASCII图像文本文件读取到二维字符数组中，先用getAsciiImageDimension函数获取文件尺寸，再将图像存储到对应尺寸的二维字符数组array中，两个函数均采用逐字符处理方式。目前代码能正确识别文件尺寸，但无法正确存储文件内容。

ascii_image.txt内容如下：

Z
 ZZZ
ZZZZZ

原代码 #

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

typedef unsigned int i32;                     // 32位无符号整数

void printTable(int rows, int columns, char table[rows][columns])
{
  for (int i = 0; i < rows; i = i + 1)
    {
      for (int j = 0; j < columns; j = j + 1)
        printf("%c", table[i][j]);

      printf("\n");
    }

  printf("\n");
}


int getAsciiImageDimension(i32* image_height, i32* image_width, const char* file_name)
{
  FILE *image = fopen(file_name, "r");

  int number_of_rows = 0;
  int row_length = 0;
  int max_row_length = 0;
  char character = (char) fgetc(image);

  while (character != EOF)
    {
      if (character == '\n')
        {
          number_of_rows = number_of_rows + 1;

          if (max_row_length < row_length)
            max_row_length = row_length;

          row_length = 0;
        }
      else
        row_length = row_length + 1;

      character = (char) fgetc(image);
    }

  *image_height = number_of_rows;
  *image_width = max_row_length;
  return 0;
}

void readAsciiImage(i32 image_height, i32 image_width, char array[image_height][image_width], const char* file_name)
{
  FILE *image = fopen(file_name, "r");
  i32 i = 0;
  i32 j = 0;

  char character = (char) fgetc(image);

  while (character != EOF)
    {
      array[i][j] = character;

      if (character == '\n')
        {
          while (j < image_width)
            {
              array[i][j] = ' ';
              j = j + 1;
            }

          i = i + 1;
        }
      else
        j = j + 1;

      character = (char) fgetc(image);
    }
}


int main()
{
  int image_width;
  int image_height;
  getAsciiImageDimension(&image_height, &image_width, "ascii_image.txt");
  printf("image_height = %d and image_width = %d \n", image_height, image_width);
  char array[image_height][image_width];
  readAsciiImage(image_height, image_width, array, "ascii_image.txt");
  printTable(image_height, image_width, array);    // 数组内容错误

  return 0;
}

编辑1：输出异常说明 #

输出的第二行为空，无法理解该现象。

编辑2：可正常运行的代码（供参考） #

#include <stdio.h>
#include <stdlib.h>
#include <math.h>


void printTable(int rows, int columns, char table[rows][columns])
{
  for (int i = 0; i < rows; i = i + 1)
    {
      for (int j = 0; j < columns; j = j + 1)
        printf("%c", table[i][j]);

      printf("\n");
    }

  printf("\n");
}


int getAsciiImageDimension(unsigned int* image_height, unsigned int* image_width, const char* file_name)
{
  FILE *image = fopen(file_name, "r");

  // 检查文件是否成功打开
  if (!image)
    {
      printf("无效文件\n");
      return -1;
    }

  int number_of_rows = 0;
  int row_length = 0;
  int max_row_length = 0;
  char character = (char) fgetc(image);

  while (character != EOF)
    {
      if (character == '\n')
        {
          number_of_rows = number_of_rows + 1;

          if (max_row_length < row_length)
            max_row_length = row_length;

          row_length = 0;
        }
      else
        row_length = row_length + 1;

      character = (char) fgetc(image);
    }
  fclose(image);
  *image_height = number_of_rows;
  *image_width = max_row_length;
  return 0;
}

void readAsciiImage(unsigned int image_height, unsigned int image_width, char array[image_height][image_width], const char* file_name)
{
  FILE *image = fopen(file_name, "r");
  unsigned int i = 0;
  unsigned int j = 0;

  char character = (char) fgetc(image);

  while (character != EOF)
    {
      array[i][j] = character;

      if (character == '\n')
        {
          while (j < image_width)
            {
              array[i][j] = ' ';
              j = j + 1;
            }

          i = i + 1;
          j = 0;  // 关键修复：换行后重置列索引j为0
        }
      else
        j = j + 1;

      character = (char) fgetc(image);
    }
  fclose(image);
}


int main()
{
  unsigned int image_width;
  unsigned int image_height;
  getAsciiImageDimension(&image_height, &image_width, "ascii_image.txt");
  printf("image_height = %d and image_width = %d \n", image_height, image_width);
  char array[image_height][image_width];
  readAsciiImage(image_height, image_width, array, "ascii_image.txt");
  printTable(image_height, image_width, array);
    
  return 0;
}

问题根源 #

原代码中readAsciiImage函数处理换行符时，仅递增行索引i，但未重置列索引j为0。导致换行后继续从当前j的位置开始写入，超出当前行的范围，进而破坏后续行的存储，出现第二行为空的异常。

内容的提问来源于stack exchange，提问作者3nondatur