The following represents a sample tree saved in a file.

The children of each node has an extra '\t'

at the beginning and the children of each

node are directly under it.

The tree can be very deep and each node can have 0 to many child nodes.

===========================

Root

V:\

FolderX

FolderA1

FolderD2

FolderB

FolderW1

FolderB2

D:\

FolderM

FolderQ1

FolderC2

============================

Please implement a program to load the whole tree into the memory from the tree file. The program should not only load the tree file above, but also load other similar tree files.

The tree data structure should be similar as.

Class Tree

{

string name;

int level; // the depth of the node from the root

Array children; // each object in the Array is the type Tree.

}

And then sort the child nodes of each node in the ascending order using IComparer interface.

Then print the tree out in the same tree file format.

差不多是用个自己作的树，递归一下就行了，不过节点类还是Tree类型，不只左右，应该可以无限多。

"level"这变量可要可不要，要是树不太深最好别要，因为如果需要作很多来回移动节点或插入的操作的话，改每个节点的level简直类死了。如果用VC里的Tree当然省了不少事，如果自己写每个孩子还要有一个指回家长的指针。

Class TreeNode
{
public:
int getLevel();
private:
string m_sName;
TreeNode *m_pParent; // NULL for root
vector<TreeNode> m_treeChildren;
};

用c++就可以了 谢谢这位大侠

没作太仔细的error handling，如果tab乱了得话应该管一管。 code中用了vector，看着不顺眼的话就换成数组8。没调的太仔细，用什么错告诉我。

程序代码：

#include <iostream>
#include <sstream>
#include <fstream>
#include <cstdlib>
#include <vector>
using namespace std;


class CTreeNode
{
public:
 CTreeNode();
 CTreeNode(string sName, CTreeNode *ptreeParent);
 string ParseChild(ifstream &ifs, int intLevel);
 CTreeNode *GetParent() {return m_ptreeParent;}
 string GetName() const {return m_sName;}
 int GetChildNumber() const {return (int)m_vecChildren.size();}
 int GetLevel();
 string ToString();
private:
 string m_sName;
 CTreeNode *m_ptreeParent;
 vector<CTreeNode> m_vecChildren;
};
CTreeNode::CTreeNode() : m_ptreeParent(NULL)
{
}
CTreeNode::CTreeNode(string sName, CTreeNode *ptreeParent)
 : m_sName(sName)
 , m_ptreeParent(ptreeParent)
{
}

int CTreeNode::GetLevel()
{
 int intLevel = 0;
 CTreeNode *pParent = m_ptreeParent;
 while (pParent)
 {
  pParent = pParent->GetParent();
  intLevel++;
 }
 return intLevel;
}
string CTreeNode::ParseChild(ifstream &ifs, int intLevel)
{
 string sLine, sCopy, sTabs = \"\t\";
 int intStart, intLevelCount;
 for (intLevelCount = 0; intLevelCount < intLevel; intLevelCount++)
  sTabs += '\t';
 // error in stream test
 while(true) 
 {
  if (sLine.empty())
   getline(ifs,sLine);
  if (ifs.eof())
   return \"\";
  if ((intStart = sLine.find(sTabs)) < 0)
   return sLine;
  sCopy = sLine;
  sCopy.erase(0, intStart+intLevel+1);
  if (sCopy.at(0) == '\t') // TODO: exception handling here
   return sLine;
  m_vecChildren.push_back(CTreeNode(sCopy, this));
  sLine = m_vecChildren[m_vecChildren.size()-1].ParseChild(ifs, intLevel+1);
 }
}
string CTreeNode::ToString()
{
 stringstream ssOutput;
 ssOutput << GetName() << \", Child Number:\" << GetChildNumber() << endl;
 for (int intChildCount = 0; intChildCount < m_vecChildren.size(); intChildCount++)
  ssOutput << m_vecChildren[intChildCount].ToString();
 return ssOutput.str();
}
ostream& operator << (ostream &o, CTreeNode& node)
{
 return o << node.ToString();
}
int main(int argc, char* argv[])
{
 string sLine;
 CTreeNode *pNodeRoot;
 ifstream ifs(\"lsttest.txt\");
 if (!ifs)
 {
  cout << \"Cannot open file\" << endl;
  return 0;
 }
 getline(ifs, sLine);
 if (ifs.eof() || sLine.empty())
  return 0;
 // initialize parent.
 pNodeRoot = new CTreeNode(sLine, NULL);
 pNodeRoot->ParseChild(ifs, 0);
 cout << *pNodeRoot;
 delete pNodeRoot;
 return 0;
}

附件是所存储的树的格式。把它更名成"listtest.txt"，就像程序里写的那样，放在正确的路径下。
ifstream ifs("lsttest.txt");
如果你们老师用别的符号表示TAB， 就把‘\t’换成该符号，例如' '。