程序应该要求用户输入他或她想要搜索的员工的ID号。如果找到,则显示该ID号的员工。我只需使用显示功能就可以显示身份证号码和员工,但我无法弄清楚如何使搜索功能工作并显示员工。
二叉树
#ifndef BINARYTREE_H
#define BINARYTREE_H
#include <iostream>
using namespace std;
// This class is a template class that creates a binary
// tree that can hold values of any data type. It has
// functions to insert a node, delete a node, display the
// tree In Order, Pre Order and Post Order, search for a
// value, count the number of total nodes, left nodes,
// and a function to determine the height of the tree.
template <class T>
class BinaryTree
{
private:
struct TreeNode
{
T value; // The value in the node
TreeNode *left; // Pointer to left child node
TreeNode *right; // Pointer to right child node
};
TreeNode *root; // Pointer to the root node
// Private member functions
void insert(TreeNode *&, TreeNode *&);
void destroySubTree(TreeNode *);
void deleteNode(T, TreeNode *&);
void makeDeletion(TreeNode *&);
void displayInOrder(TreeNode *) const;
void displayPreOrder(TreeNode *) const;
void displayPostOrder(TreeNode *) const;
public:
// Constructor
BinaryTree()
{ root = NULL; }
// Destructor
~BinaryTree()
{ destroySubTree(root); }
// Binary tree operations
void insertNode(T);
bool searchNode(int);
void remove(T);
void displayPreOrder() const
{ displayPreOrder(root); }
void displayInOrder() const
{ displayInOrder(root); }
void displayPostOrder() const
{ displayPostOrder(root); }
};
//*********************************************************
// insert function accepts a TreeNode pointer and a *
// pointer to a node. The function inserts the node into *
// the tree pointer to by the TreeNode pointer. This *
// function is call recursively. *
//*********************************************************
template <class T>
void BinaryTree<T>::insert(TreeNode *&nodePtr, TreeNode *&newNode)
{
if (nodePtr == NULL)
nodePtr = newNode; // Insert the node
else if (newNode->value < nodePtr->value)
insert(nodePtr->left, newNode); // Search the left branch
else
insert(nodePtr->right, newNode);// Search the right branch
}
//*********************************************************
// insertNode creates a new node to hold item as its value*
// and passes it to the insert function. *
//*********************************************************
template <class T>
void BinaryTree<T>::insertNode(T item)
{
TreeNode *newNode; // Pointer to a new node
// Create anew node and store num in it
newNode = new TreeNode;
newNode->value = item;
newNode->left = newNode->right = NULL;
// Insert the node
insert(root, newNode);
}
//**********************************************************
// destroySubTree is called by the destructor. It deletes *
// all nodes in the tree. *
//**********************************************************
template <class T>
void BinaryTree<T>::destroySubTree(TreeNode *nodePtr)
{
if (nodePtr)
{
if (nodePtr->left)
destroySubTree(nodePtr->left);
if (nodePtr->right)
destroySubTree(nodePtr->right);
delete nodePtr;
}
}
//**********************************************************
// searchNode determines if a value is present in the tree.*
// If so, the function returns true. Otherwise it returns *
// false.
//**********************************************************
template <class T>
bool BinaryTree<T>::searchNode(T item)
{
TreeNode *nodePtr = root;
while (nodePtr)
{
if (nodePtr->value == item)
return true;
else if (item < nodePtr->value)
nodePtr = nodePtr->left;
else
nodePtr = nodePtr->right;
}
return false;
}
//*********************************************************
// remove calls deleteNode to delete the node whode value *
// member is the same as num *
//*********************************************************
template <class T>
void BinaryTree<T>::remove(T item)
{
deleteNode(item, root);
}
//*********************************************************
// deleteNode deletes the node whose value member is the *
// same as num *
//*********************************************************
template <class T>
void BinaryTree<T>::deleteNode(T item, TreeNode *&nodePtr)
{
if (item < nodePtr->value)
deleteNode(item, nodePtr->left);
else if (item > nodePtr->value)
deleteNode(item, nodePtr->right);
else
makeDeletion(nodePtr);
}
//*********************************************************
// makeDeletion takes a reference to apointer to the node *
// that is to be deleted. The node is removed and the *
// branches of the tree below the node are reattached *
//*********************************************************
template <class T>
void BinaryTree<T>::makeDeletion(TreeNode *&nodePtr)
{
// Define a temporary pointer to use in reattaching
// the left subtree
TreeNode *tempNodePtr;
if (nodePtr == NULL)
cout << "Cannot delete empty node.\n";
else if (nodePtr->right == NULL)
{
tempNodePtr = nodePtr;
nodePtr = nodePtr->left; // Reattach the left child
delete tempNodePtr;
}
else if (nodePtr->left == NULL)
{
tempNodePtr = nodePtr;
nodePtr = nodePtr->right; // Reattach the right child
delete tempNodePtr;
}
}
//*********************************************************
// The displayInOrder function displays the values in the *
// subtree pointed to by nodePtr, via inorder traversal *
//*********************************************************
template <class T>
void BinaryTree<T>::displayInOrder(TreeNode *nodePtr) const
{
if (nodePtr)
{
displayInOrder(nodePtr->left);
cout << nodePtr->value.getEmpID() << " "
<< nodePtr->value.getEmpName() << endl;
displayInOrder(nodePtr->right);
}
}
//*********************************************************
// The displayPreOrder function displays the values in the*
// subtree pointed to by nodePtr, via Preorder traversal *
//*********************************************************
template <class T>
void BinaryTree<T>::displayPreOrder(TreeNode *nodePtr) const
{
if (nodePtr)
{
cout << nodePtr->value.getEmpID() << " "
<< nodePtr->value.getEmpName() << endl;
displayInOrder(nodePtr->left);
displayInOrder(nodePtr->right);
}
}
//*********************************************************
// displayPostOrder function displays the values in the *
// subtree pointed to by nodePtr, via Postorder traversal *
//*********************************************************
template <class T>
void BinaryTree<T>::displayPostOrder(TreeNode *nodePtr) const
{
if (nodePtr)
{
displayInOrder(nodePtr->left);
displayInOrder(nodePtr->right);
cout << nodePtr->value.getEmpID() << " "
<< nodePtr->value.getEmpName() << endl;
}
}
#endif
EMPLOYEEINFO
#ifndef EMPLOYEEINFO_H
#define EMPLOYEEINFO_H
#include <string>
#include <iostream>
using namespace std;
// This class has two data members to hold the employee ID
// and the name of the employee.
class EmployeeInfo
{
private:
int empID; // To hold employee ID number
string empName; // To hold employee name
public:
// Default Constructor
EmployeeInfo();
// Constructor
EmployeeInfo(int, string);
// Mutators
void setEmpID(int);
void setEmpName(string);
// Accessors
int getEmpID();
string getEmpName();
// Overloaded operator. This works directly with
// the insert function of BinaryTree.h more specifically
// line 71. *For my knowledge*
bool operator < (const EmployeeInfo &e)
{
if (empID < e.empID)
return true;
return false;
}
// Overloaded operator for the search function
bool operator == (const EmployeeInfo &e)
{
if (empID == e.empID)
return true;
return false;
}
};
#endif
#include "EmployeeInfo.h"
//*********************************************************
// Default constructor intializes the data members *
//*********************************************************
EmployeeInfo::EmployeeInfo()
{
empName = "";
empID = 0;
}
//*********************************************************
// Constructor sets the data members *
//*********************************************************
EmployeeInfo::EmployeeInfo(int ID, string name)
{
empName = name;
empID = ID;
}
//*********************************************************
// setEmpID stores the employee ID number *
//*********************************************************
void EmployeeInfo::setEmpID(int ID)
{
empID = ID;
}
//*********************************************************
// setEmpName stores the full name of the employee *
//*********************************************************
void EmployeeInfo::setEmpName(string name)
{
empName = name;
}
//*********************************************************
// getEmpID returns the employee ID number *
//*********************************************************
int EmployeeInfo::getEmpID()
{
return empID;
}
//*********************************************************
// getEmpName returns the full name of the employee *
//*********************************************************
string EmployeeInfo::getEmpName()
{
return empName;
}
MAIN
#include "EmployeeInfo.h"
#include "BinaryTree.h"
#include <iostream>
using namespace std;
int main()
{
// Create an instance of BinaryTree
BinaryTree<EmployeeInfo> tree;
// Create an EmployeeInfo object
EmployeeInfo emp1(1021, "John Williams");
EmployeeInfo emp2(1057, "Bill Witherspoon");
EmployeeInfo emp3(2487, "Jennifer Twain");
EmployeeInfo emp4(3769, "Sophia Lancaster");
EmployeeInfo emp5(1017, "Debbie Reece");
EmployeeInfo emp6(1275, "George McMullen");
EmployeeInfo emp7(1899, "Ashley Smith");
EmployeeInfo emp8(4218, "Josh Plemmons");
tree.insertNode(emp1);
tree.insertNode(emp2);
tree.insertNode(emp3);
tree.insertNode(emp4);
tree.insertNode(emp5);
tree.insertNode(emp6);
tree.insertNode(emp7);
tree.insertNode(emp8);
// Search for an employee
char again = 'y'; // To hold yes
int id; // To hold ID number from user
cout << "Would you like to search for an employee?\n";
cout << "Enter Y for yes or N for No: ";
cin >> again;
if (again)
{
do
{
cout << "Enter the ID number of the employee: ";
cin >> id;
// Create an EmployeeInfo object to store the user's
// search parameters
EmployeeInfo info;
info.setEmpID(id);
// If search finds what the user entered display the
// corresponding employee
if (tree.searchNode(info))
{
cout << info.getEmpName() << endl; // Not right?
}
else
cout << "ID not found!" << endl;
cout << "Would you like to search for an employee?\n";
cout << "Enter Y for yes or N for No: ";
cin >> again;
}while (again == tolower('Y'));
}
// Display in order
tree.displayInOrder();
cout << endl;
tree.displayPreOrder();
cout << endl;
tree.displayPostOrder();
}
好的,我更改了代码以使bool工作和if (tree.searchNode(info))
,但我不认为cout
语句是正确的。有人可以查看我的searchNode
函数以及我如何在main中调用它并让我知道我做错了什么?
答案 0 :(得分:1)
问题出在这里
info.setEmpID(1021);
info.setEmpID(1057);
info.setEmpID(2487);
info.setEmpID(3769);
info.setEmpID(1017);
info.setEmpID(1275);
info.setEmpID(1899);
info.setEmpID(4218);
info.setEmpName("John Williams");
info.setEmpName("Bill Witherspoon");
info.setEmpName("Jennifer Twain");
info.setEmpName("Sophia Lancaster");
info.setEmpName("Debbie Reece");
info.setEmpName("George McMullen");
info.setEmpName("Ashley Smith");
info.setEmpName("Josh Plemmons");
您没有向信息添加任何内容,但每次致电setEmpName()
时,您都在更新info
个对象。
您可以在searchNode
方法中进行少量更改,如下所示
template <class T>
bool BinaryTree :: searchNode(T&amp; item) { TreeNode * nodePtr = root;
while (nodePtr)
{
if (nodePtr->value == item)
{
item.setEmpName(nodePtr->value.getEmpName());
return true;
}
else if (item < nodePtr->value)
nodePtr = nodePtr->left;
else
nodePtr = nodePtr->right;
}
return false;
}
在main()
方法
do
{
cout << "Enter the ID number of the employee: ";
cin >> id;
BinaryTree<EmployeeInfo> temp;
if ((temp=tree.searchNode(id))!=NULL)
{
cout << temp.getEmpName() << endl;
}
else{
cout<<"ID not found"<<endl;
}
cout << "Would you like to search for an employee?\n";
cout << "Enter Y for yes or N for No: ";
cin >> again;
}while (again == tolower('Y'));
//新变化......
将searchNode(T)
的声明更改为searchNode(T &)
...在您的新代码中,info
未设置找到的员工姓名,这就是为什么当您尝试打印时EmpName
没有输出......所以更改是将EmployeeInfo
的引用传递给searchitem(T &)
模板 bool BinaryTree :: searchNode(T&amp; item) { TreeNode * nodePtr = root;
while (nodePtr)
{
if (nodePtr->value == item)
{
item.setEmpName(nodePtr->value.getEmpName());
return true;
}
else if (item < nodePtr->value)
nodePtr = nodePtr->left;
else
nodePtr = nodePtr->right;
}
return false;
}