使用文件处理的C ++中的通讯录

需要直接掌握语言和文件处理方面的知识。因此，让我们讨论文件处理和循环中的C++语言概念。我们知道，对于代码的编译， 需要一个用于编译C++语言的IDE，例如代码块，Visual Studio代码，Dev C++等，才能运行我们的程序。

该软件旨在使用文件处理功能以C++的形式添加联系人簿。在C++中，文件主要通过使用fstream头文件中可用的三个类fstream，ifstream和ofstream来处理。

• ofstream：要写入文件的流类
• ifstream：流类以从文件读取
• fstream：流类以读取和写入文件。

执行：

联系人将被保存到文件中。联系人簿将为用户提供以下功能：

1. Add contact.
2. Search Contact.
3. Help.
4. Exit.

将保存的联系方式如下：

1. First name.
2. Last name.
3. Phone Number.

例子

C++

// Importing input output operations file
#include 
// Importing file class
#include 
// Importing standard library file
#include 
  
using namespace std;
  
// Variables declared outside any function
// hence scope is global, hence global variables
string fname, lname, phone_num;
  
// Methods
  
// Helper Methods followed by
// Main driver method
  
void addContact();
void searchContact();
void help();
void self_exit();
bool check_digits(string);
bool check_numbers(string);
  
// Method 1
// Helper method
void self_exit()
{
    system("cls");
    cout << "\n\n\n\t\tThank You for using Contact-Saver!";
    exit(1);
}
  
// Method 2
// Helper method
void help()
{
    cout << "Help Center";
    cout << endl << endl;
    system("pause");
    system("cls");
}
  
// Method 3
// Helper method
void addContact()
{
    ofstream phone("number.txt", ios::app);
    system("cls");
    cout << "\n\n\tEnter First Name : ";
    cin >> fname;
    cout << "\n\tEnter Last Name : ";
    cin >> lname;
    cout << "\n\tEnter Phone Number : ";
    cin >> phone_num;
  
    if (check_digits(phone_num) == true) {
        if (check_numbers(phone_num) == true) {
            if (phone.is_open()) {
                phone << fname << " " << lname << " "
                      << phone_num << endl;
                cout << "\n\tContact saved successfully !";
            }
            else {
                cout << "\n\tError in opening record!";
            }
        }
        else {
            cout << "\n\tOnly numbers are allowed!";
        }
    }
    else {
        cout << "\n\tPhone number should be of 10 digits "
                "only.";
    }
    cout << endl << endl;
    system("pause");
    system("cls");
    phone.close();
}
  
// Method 4
// Helper method
void searchContact()
{
    bool found = false;
    ifstream myfile("number.txt");
    string keyword;
    cout << "\n\tEnter Name to search : ";
    cin >> keyword;
    while (myfile >> fname >> lname >> phone_num) {
        if (keyword == fname || keyword == lname) {
            system("cls");
            cout << "\n\n\n\t\tCONTACT DETAILS";
            cout << "\n\nFirst Name : " << fname;
            cout << "\nLast Name : " << lname;
            cout << "\nPhone Number : " << phone_num;
            found = true;
            break;
        }
    }
    if (found == false)
        cout << "\nNo such contact is found!";
  
    cout << endl << endl;
    system("pause");
    system("cls");
}
  
// Method 5
// Helper method
bool check_digits(string x)
{
    if (x.length() == 10)
        return true;
    else
        return false;
}
  
// Method 6
// Helper method
bool check_numbers(string x)
{
    bool check = true;
  
    for (int i = 0; i < x.length(); i++) {
        if (!(int(x[i]) >= 48 && int(x[i]) <= 57)) {
            check = false;
            break;
        }
    }
  
    if (check == true)
        return true;
  
    if (check == false)
        return false;
  
    cout << endl << endl;
    system("pause");
    system("cls");
}
  
// Method 7
// Main driver method
int main()
{
    int choice;
    system("cls");
    system("color 0A");
    while (1) {
        cout << "\n\n\n\t\t\tCONTACT SAVER";
        cout << "\n\n\t1. Add Contact\n\t2. Search "
                "Contact\n\t3. Help\n\t4. Exit\n\t> ";
        cin >> choice;
  
        // Switch case
        switch (choice) {
        case 1:
            addContact();
            break;
  
        case 2:
            searchContact();
            break;
  
        case 3:
            help();
            break;
  
        case 4:
            self_exit();
            break;
  
        default:
            cout << "\n\n\tInvalid Input!";
        }
    }
    return 0;
}

输出

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