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读取一个格式良好的XML文档,并按层次编号并输出
作者:佚名  文章来源:不详  点击数  更新时间:2008/10/22 21:33:22  文章录入:杜斌  责任编辑:杜斌

  #include <stdio.h>
  #include <memory.h>
  #include <string.h>
  #include <ctype.h>
  #define BUFSIZE 30
  //XML文档结点
  struct Node
  {
  int num; //结点编号
  char name[BUFSIZE]; //结点名
  char value[BUFSIZE]; //结点值
  Node *parent; //父结点;
  Node *lsibling; //左同胞结点
  Node *rsibling; //右同胞结点
  Node *firstChild; //第一个子结点
  Node *lastChild; //最后一个子结点
  int childCount; //Examda提示: 子结点个数,这个可以不要,有这个要方便些,在插入和删除子结点时要维护
  };
  //从文件中读一个字符串,直到读到标记符为此
  void ReadString(FILE *fp, char *buf)
  {
  char ch;
  char *p = buf;
  ch = fgetc(fp);
  do
  {
  if (p != buf || !isspace(ch)) //自动去掉首部空白
  {
  *(p++) = ch;
  }
  ch = fgetc(fp);
  }while (!feof(fp) && (ch != '<' && ch != '>' || p == buf));
  if ('<' == ch) //下一个标记开始
  {
  fseek(fp, -1, SEEK_CUR);
  p--;
  }
  else if ('>' == ch)
  {
  *p = ch;
  }
  //以下代码为去掉buf的尾空白
  while (p != buf && isspace(*p)) p--;
  *(++p) = '\0';
  }
  //从文件中读取一个结点及其所有子结点
  void ReadNode(FILE *fp, Node *node)
  {
  char buf[BUFSIZE];
  Node *child = NULL; //当前子结点
  ReadString(fp, buf); //读入开始标记
  strcpy(node->name, &buf[1]); //只拷贝标记正文
  node->name[strlen(node->name) - 1] = '\0';
  while (1)
  {
  buf[0] = '\0';
  ReadString(fp, buf); //读入下一个字符串
  if ('<' == buf[0]) //读到标记
  {
  if ('/' == buf[1]) //是结束标记
  {
  break; //本层结束
  }
  else //遇到开始标记,是子结点
  {
  Node *p = new Node;
  memset(p, 0, sizeof(Node));
  p->parent = node;
  if (child) //如果当前子结点不为空
  {
  child->rsibling = p;
  p->lsibling = child;
  }
  else //为第一个子结点
  {
  node->firstChild = p;
  }
  fseek(fp, -(long)strlen(buf), SEEK_CUR); //将文件指针拨回开始标记之前
  ReadNode(fp, p);
  child = p;
  node->childCount ++; //子结点个数加一
  }
  }


  else //是结点值
  {
  strcpy(node->value, buf);
  }
  }
  node->lastChild = child; //最后一个子结点
  }
  //按层次访问所有结点并编号
  void GetNum(Node *node)
  {
  static int num = 1;
  if (!node) return;
  node->num = num++;
  if (node->rsibling) //本层还未结束
  GetNum(node->rsibling);
  else if (node->parent)
  {
  if (node->parent->rsibling) //找到右堂兄弟
  GetNum(node->parent->rsibling->firstChild);
  else //进下一层
  GetNum(node->parent->firstChild->firstChild);
  }
  else //本结点是根结点,直接进入下一层
  GetNum(node->firstChild);
  }
  //按层次打印所有结点
  void PrintNode(Node *node)
  {
  if (!node) return;
  printf("Element %d - %s: %s, child:",
  node->num, node->name,
  strlen(node->value) ? node->value : "null");
  Node *p = node->firstChild;
  if (!p) printf("null");
  while (p)
  {
  printf("Element %d", p->num);
  p = p->rsibling;
  if (p) printf(", ");
  }
  printf("\n");
  if (node->rsibling) //本层还未结束
  PrintNode(node->rsibling);
  else if (node->parent)
  {
  if (node->parent->rsibling) //找到右堂兄弟
  PrintNode(node->parent->rsibling->firstChild);
  else //进下一层
  PrintNode(node->parent->firstChild->firstChild);
  }
  else //本结点是根结点,直接进入下一层
  PrintNode(node->firstChild);
  }
  //释放结点树
  void FreeNode(Node *node)
  {
  Node *p = node->firstChild;
  while (p)
  {
  Node *q = p->rsibling;
  FreeNode(p);
  p = q;
  }
  delete node;
  }
  void main()
  {
  char filename[BUFSIZE];
  FILE *fp;
  printf("Please enter XML filename:");
  scanf("%s", filename);
  if (!(fp = fopen(filename, "r")))
  {
  printf("Open file %s fail!\n");
  }
  else
  {
  Node *node = new Node;
  memset(node, 0, sizeof(Node));
  ReadNode(fp, node);
  fclose(fp);
  GetNum(node);
  PrintNode(node);
  FreeNode(node);
  }
  } 来源:考试大网
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