Question

我的目标是将文件的非注释行打印到屏幕或输出文件，无论如何指定。我的代码在两种情况下工作正常（即我得到了所需的输出）但是，当我将线条打印到屏幕上时，它工作正常，并且在打印完所有内容后，它显示Segmentation fault (core dumped)

这是我的代码：

/* Assignment 1 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <ctype.h>

#define MAXS 256

int main(int argc, char *argv[])
{
  FILE *fp;
  FILE *op;
  char line[MAXS] = {0};
  int max_x, max_y, num_pt, rand_inst;
  int ch;
  int inputfile = 0, outputfile = 0;
  int i;


  for (i = 1; i < argc; i++)
    {
      if (strcmp (argv[i], "-i") == 0)
    inputfile = i+1;
      if (strcmp (argv[i], "-o") == 0)
    outputfile = i+1;
    }
  if (inputfile == 0)
    {
      /* invalid command line options */
      printf("\nIncorrect command-line...\n");
      printf("> %s [-i inputfile [-o outputfile]]\n\n", argv[0]);
      exit(0);
    }

  fp = fopen(argv[inputfile], "r");
  if (fp == 0)
    {
      printf("\nCould not find %s\n", argv[inputfile]);
      exit(0);
    }
 /* while ((ch = fgetc(fp)) != EOF)) */

 /* This part is where I get the error but I get the desired output */
  if (outputfile == 0)
    {
      while (fgets (line, MAXS, fp) != NULL) 
        {         
          char *p = line;
          size_t len = strlen (line);

          while (len > 0 && (line[len-1] == '\n' || line[len-1] == '\r'))
                line[--len] = 0;    /* strip newline or carriage rtn    */


          while (isspace (*p))  /*  advance to first non-whitespace  */
                p++;

          /* skip lines beginning with '#' or blank lines  */
          if (*p == '#' || !*p)
                continue;

          printf("%s\n", line);

        }
    }
  else
    {
      op = fopen(argv[outputfile], "w");
      while (fgets (line, MAXS, fp) != NULL) 
        {
          char *p = line;

          size_t len = strlen (line);

          while (len > 0 && (line[len-1] == '\n' || line[len-1] == '\r'))
                line[--len] = 0;    /* strip newline or carriage rtn    */


          while (isspace (*p))  /*  advance to first non-whitespace  */
                p++;

          /* skip lines beginning with '#' or blank lines  */
          if (*p == '#' || !*p)
                continue;

          fprintf(op, "%s\n", line);

        }
    }
  fclose(op);

  return 0;
}

这是输出，它给我分段错误：

100 100

10

0 0

0 90

70 100

100 50

30 30

30 70
     <70> 70 70

70 30

50 50

45 0

分段错误（核心转储）

然而，上面是所需的输出减去分段故障错误

我知道分段错误与读取/写入非法内存位置有关，但我无法弄清楚为什么程序给我错误，前提是我没有编译错误而且我得到了期望的输出

语言：c99;编译器：gcc

Answer 1

seg错误是由您的上一行op引起的。我怀疑NULL是fclose或无效的内存位置（即垃圾），这导致了seg错误。

除了在else语句中粘贴bool check(int wins[], int number) { for (int i = 0; i <= arraySize; ++i) if (number == wins[i]) { return true; } else if (number != wins[i]) { return false; } }（如评论中所述）...我还会初始化这些文件指针。

分段错误（核心转储）错误，但程序运行正常

1 个答案: