问题
我正在构建一个电话簿程序，该程序允许用户执行各种操作，例如添加，查找，编辑和删除联系信息。有了这些，它将不断地发送到文本文件，并在需要时更新文本文件中的数据。
我的问题是，如果我添加一个联系人“ A”，关闭程序，添加另一个联系人“ B”，我的文本文件将覆盖以前的内容，只有“ B”。我希望联系人“ A”和“ B”都在其中。
尝试
在我的appendToFile函数中（需要更改名称，因为它会覆盖而不是追加），我知道每次运行该程序时，它将使用新的电话簿覆盖信息。我之所以选择不附加，是因为当我使用其他功能（例如编辑联系人和删除联系人）时，它应该通过覆盖文件来更新文件。
问题
我如何使用txt中的现有数据，使用该信息填充我的phoneBook []，并保留所有现有数据，同时能够添加新联系人而不删除现有数据？
代码
.h
#include <string>
#include <iostream>
#include <fstream>
#include <algorithm>
#pragma once
class Contact
{
public:
Contact();
std::string firstName;
std::string lastName;
std::string name; //lName + fName
std::string phoneNumber;
std::string address;
};
class AddressBook
{
private:
Contact contact;
std::ofstream myFile;
int length;
static const int maxSize = 10;
Contact* phoneBook[maxSize]; //array of contact pointers
public:
AddressBook();
void addContact(std::string fName, std::string lName, std::string pNumber, std::string addr); //good
void deleteContact(std::string nameMatch); //fix
int findContact(std::string name);
void editContact();
void getCurrent(); //good
void makeEmpty(); //good
bool isFull(); //good
bool isEmpty();
void bubbleSort(Contact* phoneBook[], int n);
void appendToFile(Contact* phoneBook[]);
//int validation(Contact* phoneBook[]); //checks if name has numbers or not
~AddressBook();
};
#include "AddressBook.h"
AddressBook::AddressBook()
{
length = 0;
phoneBook[maxSize];
}
void AddressBook::addContact(std::string fName, std::string lName, std::string pNumber, std::string addr)
{
// need validation
if (isFull())
{
std::cout << "Is full" << std::endl;
return;
}
Contact *contact = new Contact;
contact->firstName = fName;
contact->lastName = lName;
contact->name = lName + ", " + fName;
contact->phoneNumber = pNumber;
contact->address = addr;
std::cout << contact->name + " has been added!" << std::endl;
phoneBook[length] = contact;
length++;
bubbleSort(phoneBook, length);
appendToFile(phoneBook);
}
void AddressBook::deleteContact(std::string nameMatch) //need to implement find contact && not found if there is a space at end of name
{
if (isEmpty() != true)
{
auto position = findContact(nameMatch);
if (position != -1) //contact not found
{
std::cout << phoneBook[position]->name << " deleted" << std::endl;
phoneBook[position] = phoneBook[length - 1];
length--;
}
bubbleSort(phoneBook, length);
appendToFile(phoneBook);
}
return;
}
.cpp
int AddressBook::findContact(std::string nameMatch)
{
//implements binary search
if (isEmpty() != true)
{
int first = 0;
int last = length - 1;
int middle;
int position = -1;
bool found = false;
while (!found && first <= last)
{
middle = (first + last) / 2;
if (phoneBook[middle]->name == nameMatch)
{
found = true;
position = middle;
}
else if (phoneBook[middle]->name > nameMatch)
{
last = middle - 1;
}
else
{
first = middle + 1;
}
}
if (found == false)
{
std::cout << "Person: " << nameMatch << " was not found" << std::endl;
}
if (found == true)
{
std::cout << phoneBook[position]->name << std::endl;
std::cout << phoneBook[position]->phoneNumber << std::endl;
std::cout << phoneBook[position]->address << std::endl;
}
return position;
}
return 0;
}
void AddressBook::editContact() //needs to update file
{
if (isEmpty() != true)
{
std::string fName, lName, newfName, newlName, newName, newpNum, newAddr, nameMatch;
//enter old info
std::cout << "Enter the first name of the contact you want to edit: ";
std::cin.ignore();
std::getline(std::cin, fName);
std::cout << "Enter the last name of the contact: ";
std::getline(std::cin, lName);
nameMatch = lName + ", " + fName;
auto position = findContact(nameMatch);
if (position != -1)
{
//enter new (edited) info
std::cout << "Enter the new first name: ";
getline(std::cin, newfName);
std::cout << "Enter the new last name: ";
getline(std::cin, newlName);
newName = newlName + ", " + newfName;
phoneBook[position]->name = newName;
phoneBook[position]->firstName = newfName;
phoneBook[position]->lastName = newlName;
std::cout << "Enter the new phone number: ";
getline(std::cin, newpNum);
phoneBook[position]->phoneNumber = newpNum;
std::cout << "Enter the new address: ";
getline(std::cin, newAddr);
phoneBook[position]->address = newAddr;
}
}
appendToFile(phoneBook);
}
void AddressBook::getCurrent()
{
if (isEmpty() != true)
{
std::cout << "Name: " << phoneBook[length - 1]->name << std::endl;
std::cout << "Phone Number: " << phoneBook[length - 1]->phoneNumber << std::endl;
std::cout << "Address: " << phoneBook[length - 1]->address << std::endl;
}
}
void AddressBook::makeEmpty()
{
length = 0;
}
bool AddressBook::isFull()
{
if (length == maxSize)
{
return true;
}
else
{
return false;
}
}
bool AddressBook::isEmpty()
{
if (length == 0)
{
std::cout << "Phonebook is empty" << std::endl;
return true;
}
return false;
}
void AddressBook::bubbleSort(Contact * phoneBook[], int n)
{
if (!isEmpty())
{
Contact* temp;
int j = 0;
for (int i = 0; i < length; i++)//for n-1 passes
{
for (int j = 0; j < length - 1; j++)
{
if (phoneBook[j]->name > phoneBook[j + 1]->name)
{
temp = phoneBook[j];
phoneBook[j] = phoneBook[j + 1];
phoneBook[j + 1] = temp;
}
}
}
}
}
void AddressBook::appendToFile(Contact* phoneBook[])
{
myFile.open("fileName.txt", std::ios::out);
if (!myFile)
{
std::cerr << "Error: file could not be opened." << std::endl;
return;
}
for (int i = 0; i < length; i++)
{
myFile << std::endl << phoneBook[i]->name << std::endl;
myFile << phoneBook[i]->phoneNumber << std::endl;
myFile << phoneBook[i]->address << std::endl;
std::cout << std::endl << std::endl;
}
myFile.close();
}
/*
int AddressBook::validation(Contact * phoneBook[])
{
for (int i = 0; i < phoneBook[length]->name.length; i++)
{
if (isalpha(phoneBook[i]->name)==0)
{
}
}
return false;
}
*/
AddressBook::~AddressBook()
{
//delete ?
}
Contact::Contact()
{
std::string fName = "empty";
std::string lName = "empty";
std::string pNumber = "xxx-xxx-xxxx";
std::string addr = "empty";
}
来源
#include "AddressBook.h"
using namespace std;
int main()
{
AddressBook addrBook;
string fName, lName, pNum, addr, nameMatch;
int choice;
char input;
do
{
cout << endl << "Phone Book" << endl << endl;
cout << "1. Add Contact" << endl;
cout << "2. Find Contact" << endl;
cout << "3. Edit Contact" << endl;
cout << "4. Delete Contact" << endl;
cout << "5. Display Current Contact" << endl;
cout << "0. Quit" << endl;
do
{
cout << endl << "What is your choice?" << endl;
cin >> choice;
if (choice < 0 || choice >= 6)
cout << "That's not an option. Try again." << endl;
} while (choice < 0 || choice >= 6);
switch (choice) //need to fix menu
{
case 1:
cout << "Enter your information." << endl;
cout << "First name: ";
cin >> fName;
cout << "Last name: ";
cin >> lName;
cout << "Phone Number: ";
cin.ignore();
getline(cin, pNum, '\n');
cout << "Address: ";
getline(cin, addr, '\n');
cout << endl;
addrBook.addContact(fName, lName, pNum, addr);
break;
case 2: //finds contact but couts nothing
cout << "Find Contact" << endl;
cout << "Enter the name of the contact you want to find." << endl;
cout << "First name: ";
cin >> fName;
cout << "Last name: ";
cin >> lName;
nameMatch = lName + ", " + fName;
cout << endl;
addrBook.findContact(nameMatch);
break;
case 3:
addrBook.editContact();
break;
case 4:
cout << "Delete Contact" << endl;
cout << "Enter the first name of the contact you want to delete: ";
cin.ignore();
getline(cin, fName);
cout << "Enter the last name of the contact you want to delete: ";
getline(cin, lName);
nameMatch = lName + ", " + fName;
addrBook.deleteContact(nameMatch);
break;
case 5:
cout << "Display Current Contact" << endl;
addrBook.getCurrent();
break;
case 0:
cout << "Goodbye" << endl;
exit(0);
break;
}
cout << "Would you like to continue? (Y/N): ";
cin >> input;
system("CLS");
} while (input == 'Y' || input == 'y');
return 0;
}**