C++ implementation of linked list version address book

This article example Shared C++ for you to realize the linked list version of the address book specific code, for your reference, specific content is as follows

#include <iostream>
#include <string>
using namespace std;
class Address;
 
class Contact{
private:
 string name;
 string sex;
 string tel;
 string QQ;
 string address;
 string addition;
 Contact *next;
public:
 Contact();
 friend class Address; 
 
};
Contact::Contact()
{
 next = NULL;
}
class Address{
public:
 Address();
 ~Address();
 int show();
 void insert();
 void delete_per();
 void display();
 void search();
 void update(); 
private:
 Contact *head;
};
Address::Address()
{
 head = new Contact;
 if(head == NULL)
 {
 cout<<"fail create"<<endl;
 }
}
Address::~Address()
{
 delete head;
}
int Address::show()  // Main menu function 
{
 int choice = 0 ;
 cout<<"\t\t\t\t**************************"<<endl;
 cout<<"\t\t\t\t*  The address book c++ The simple version  *"<<endl;
 cout<<"\t\t\t\t**************************"<<endl;
 cout<<"\t\t\t\t* 1 , add  2 , delete,   *"<<endl;
 cout<<"\t\t\t\t**************************"<<endl;
 cout<<"\t\t\t\t* 3 And check  4 , search,   *"<<endl;
 cout<<"\t\t\t\t**************************"<<endl;
 cout<<"\t\t\t\t* 5 , update,  6 , exit   *"<<endl;
 cout<<"\t\t\t\t**************************"<<endl;
 cout<<"\t\t\t\t Please enter options: ";
 cin>>choice;
 while(!(choice >= 1&&choice <= 6))
 {
 while(getchar()!='\n');
 cout<<" Input error, please re-input! ";
 cin>>choice;
 }
 return choice;
 
}
void Address::insert() // Add contacts 
{
 Contact *p = head;
 char relay = 0;
 while(p->next != NULL)
 {
 p = p->next;
 }
 Contact *person = new Contact;
 cout<<" Please enter your name: ";
 cin>>person->name;
 cout<<" Please enter gender: ";
 cin>>person->sex;
 cout<<" Please enter the telephone number: ";
 cin>>person->tel;
 cout<<" Please enter the QQ : ";
 cin>>person->QQ;
 cout<<" Please enter address: ";
 cin>>person->address;
 cout<<" Please enter comments: ";
 cin>>person->addition;
 p->next = person;
 person->next = NULL;
 cout<<"\n Add successfully. Do you want to continue? ( y/n ) ";
 cin>>relay;
 while(!(relay == 'y'||relay == 'Y'||relay == 'N'||relay == 'n'))
 {
 cout<<" Input error, please re-enter ( y/n ) : ";
 cin>>relay;
 }
 if(relay == 'y'||relay == 'y')
 {
 system("clear");
 insert();
 }
}
void Address::delete_per() // Delete contacts 
{
 string m_name;
 Contact *p = head;
 Contact *pre = head;
 int flag = 0;
 cout<<" Please enter the name of the contact you want to delete! ";
 cin>>m_name;
 while(p->next != NULL)
 {
 pre = p;
 p = p->next;
 if(p->name == m_name)
 {
 pre->next = p->next;
 delete p;
 p = NULL;
 flag = 1;
 break;
 }
 }
 if(flag == 1)
 {
 cout<<" Delete successful! "<<endl;
 }
 else
 {
 cout<<" The contact you deleted does not exist, delete failed! "<<endl;
 }
}
 
void Address::display() // View contacts  
{
 Contact *p = head;
 while(p->next != NULL)
 {
 p = p->next;
 cout<<endl<<"======================================="<<endl;
 cout<<" Name: "<<p->name<<endl;
 cout<<" Gender: "<<p->sex<<endl;
 cout<<" Telephone: "<<p->tel<<endl;
 cout<<"QQ : "<<p->QQ<<endl;
 cout<<" Address: "<<p->address<<endl;
 cout<<" Remark: "<<p->addition<<endl; 
 }
 
}
void Address::search() // Search contacts 
{
 string m_name;
 Contact *p = head;
 int flag = 0;
 cout<<" Please enter the name of the contact you are searching for :";
 cin>>m_name;
 while(p->next != NULL)
 {
 p = p->next;
 if(p->name == m_name)
 {
 cout<<endl<<"======================================="<<endl;
 cout<<" Name: "<<p->name<<endl;
 cout<<" Gender: "<<p->sex<<endl;
 cout<<" Telephone: "<<p->tel<<endl;
 cout<<"QQ : "<<p->QQ<<endl;
 cout<<" Address: "<<p->address<<endl;
 cout<<" Remark: "<<p->addition<<endl; 
 flag = 1;
 }
 }
 if(flag == 1)
 {
 cout<<"\n Query successful! "<<endl;
 }
 else
 {
 cout<<" The contact you inquired does not exist, delete failed! "<<endl;
 }
}
void Address::update() // Modify contact 
{
 Contact *p = head;
 string m_name;
 int flag = 0;
 
 cout<<" Please enter the name you want to update: ";
 cin>>m_name;
 while(p->next != NULL)
 {
 p = p->next;
 if(p->name == m_name)
 {
 cout<<" Please update gender: ";
 cin>>p->sex;
 cout<<" Please update your phone number: ";
 cin>>p->tel;
 cout<<" Please update QQ : ";
 cin>>p->QQ;
 cout<<" Please update your address: ";
 cin>>p->address;
 cout<<" Please update comments: ";
 cin>>p->addition;
 flag = 1;
 break;
 }
 }
 if(flag == 1)
 {
 cout<<"\n The update is successful "<<endl;
 }
 else
 {
 cout<<" Check no this person, update failed! "<<endl;
 }
}
 
int main()
{
 Address *person = new Address;
 int choice = 0;
 while(1)
 {
 system("clear");
 choice = person->show();
 switch(choice)
 {
 case 1:
 {
 system("clear");
 person->insert();
 break;
 }
 case 2:
 {
 system("clear");
 person->delete_per();
 break;
 }
 case 3:
 {
 system("clear");
 person->display();
 break;
 }
 case 4:
 {
 system("clear");
 person->search();
 break;
 }
 case 5:
 {
 system("clear");
 person->update();
 break;
 }
 case 6:
 {
 exit(0);
 }
 }
 cout<<"\n\n Press any key to return .....";
 getchar();
 getchar();
 }
 return 0;
}