Question:
struct NODE {
NODE* pLeft;
NODE* pRight;
char chValue;
};
e.g.
preorder traversal : a b d c e f
inorder traversal : d b a e c f

Answer:

#include <iostream>

using namespace std;

struct NODE {
  NODE* pLeft;
  NODE* pRight;
  char chValue;
};

void PrintPreOrder(NODE* pRoot) {
  if (!pRoot)
    return;
  cout << pRoot->chValue;
  PrintPreOrder(pRoot->pLeft);
  PrintPreOrder(pRoot->pRight);
}

void PrintInOrder(NODE* pRoot) {
  if (!pRoot)
    return;
  PrintInOrder(pRoot->pLeft);
  cout << pRoot->chValue;
  PrintInOrder(pRoot->pRight);
}

void Rebuild(char* pPreOrder, char* pInOrder, int nTreeLen, NODE** pRoot) {
  if (pPreOrder == 0 || pInOrder == 0)
    return;
  NODE* pTemp = new NODE;
  pTemp->pLeft = 0;
  pTemp->pRight = 0;
  pTemp->chValue = *pPreOrder;
  if (*pRoot == 0)
    *pRoot = pTemp;
  if (nTreeLen == 1)
    return;
  char* pOrgInOrder = pInOrder;
  char* pLeftEnd = pInOrder;
  int nTempLen = 0;
  while (*pPreOrder !=  *pLeftEnd) {
    nTempLen++;
    if (nTempLen > nTreeLen)
      break;
    pLeftEnd++;
  }
  int nLeftLen = (int)(pLeftEnd - pOrgInOrder);
  int nRightLen = nTreeLen - nLeftLen - 1;
  if (nLeftLen > 0)
    Rebuild(pPreOrder+1, pInOrder, nLeftLen, &(pTemp->pLeft));
  if (nRightLen > 0)
    Rebuild(pPreOrder+nLeftLen+1, pInOrder + nLeftLen + 1, nRightLen, &(pTemp->pRight));
}

int main() {
  char* pPreOrder = "abdcef";
  char* pInOrder = "dbaecf";
  NODE* pRoot = 0;
  int nTreeLen = 6;
  Rebuild(pPreOrder, pInOrder, nTreeLen, &pRoot);
  PrintPreOrder(pRoot);
  cout << endl;
  PrintInOrder(pRoot);
  cout << endl;
  return 0;
}