解析章节时的Coredump

Question

我正在做一项阅读一本书的家庭作业。首先，读入一行并使指针指向该行。然后一个段落函数读取行并将它们的地址存储到一个指针数组中。现在，我正在阅读一章(下一行被打破的段落)。它应该调用 get_paragraph() 并存储段落的地址，直到到达新的章节。

新章节是书中唯一一次第一个字符不是空格的情况。我认为这是我的代码有问题。到目前为止的所有功能都可以工作。我希望我已经提供了足够的信息。代码编译但启动时核心转储。

我是一名学生，正在学习，所以请善待。谢谢。

char*** get_chapter(FILE * infile){

    int i=0;

    char **chapter[10000];//an array of pointers 
    // Populate the array
    while(chapter[i]=get_paragraph(infile)) { //get address store into array
      if(!isspace(**chapter[0])){    //check to see if it is a new chapter<---problem line?
        // save paragraph not used in chapter using static to put into next chapter
        break;
      }
      i++;//increment array
    }
    //add the null
    chapter[++i]='\0';//put a null at the end to signify end of array
    //Malloc the pointer
    char**(*chap) = malloc(i * sizeof(*chap));//malloc space
    //Copy the array to the pointer
    i=0;//reset address
    while(chapter[i]){//while there are addresses in chapter
      chap[i] = chapter[i++];//change addresses into chap
    }
    chap[i]='\0';//null to signify end of chapter
    //Return the pointer
    return(chap);//return pointer to array
  }

对于那些宁愿看到没有评论的人:

 char*** get_chapter(FILE * infile){

    int i=0;

    char **chapter[10000];
    while(chapter[i]=get_paragraph(infile)) { 
      if(!isspace(**chapter[0])){   
        break;
      }
      i++;
    }
    chapter[++i]='\0';
    char**(*chap) = malloc(i * sizeof(*chap));//malloc space
    i=0;
    while(chapter[i]){
      chap[i] = chapter[i++];
    }
    chap[i]='\0';
    return(chap);
  }

Answer 1

内联评论。

char*** get_chapter(FILE * infile) {
  int i=0;

  // This is a zero length array!
  // (The comma operator returns its right-hand value.)
  // Trying to modify any element here can cause havoc.
  char **chapter[10,000];

  while(chapter[i]=get_paragraph(infile)) { 
    // Do I read this right? I translate it as "if the first character of 
    // the first line of the first paragraph is not whitespace, we're done."
    // Not the paragraph just read in -- the first paragraph.  So this will exit
    // immediately or else loop forever and walk off the end of the array
    // of paragraphs.  I think you mean **chapter[i] here.
    if(!isspace(**chapter[0])){   
      break;
    }
    i++;
  }

  // Using pre-increment here means you leave one item in the array uninitialized
  // which can also cause a fault later on.  Use post-increment instead.
  // Also '\0' here is the wrong sort of zero; I think you need NULL instead.
  chapter[++i]='\0';

  char**(*chap) = malloc(i * sizeof(*chap));
  i=0;
  while(chapter[i]) {
    // This statement looks ambiguous to me.  Referencing a variable twice and
    // incrementing it in the same statement?  You may end up with an off-by-one error.
    chap[i] = chapter[i++];
  }

  // Wrong flavor of zero again.
  chap[i]='\0';
  return(chap);
}