c++ - C++ でリストをアルファベット順に並べ替える方法

Question

最終プロジェクトのコードで問題が発生しています。いろいろ調べて困っていたのでこちらで質問させていただきました。すべての名前がこの電話帳にリストされているときに、アルファベット順に出てくることを確認する必要がありますが、それを行う方法はまだわかりません. これが私が現在持っているプログラムです！ありがとうございました！

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>

using namespace std;

struct Contact {
   string name, number, notes;
};

Contact contactList[100];
int rec_num = 0;
int num_entries;

string toUpper (string S) {
   for (int i= 0; i < S.length(); i++)
      S[i] = toupper(S[i]);
   return S;
}

void ReadFile () {
   string S;
   fstream input("PhoneData.txt");
   while (!input.eof() && !input.fail()){
      input >> contactList[rec_num].name >> contactList[rec_num].number;
      getline(input, S);
      contactList[rec_num].notes = S;
      rec_num++;
   }
   cout << "Book read." << endl;
   num_entries = rec_num;
   input.close();
   return;
}

// stores phonebook for future runs of the program
void StoreFile () {
   fstream F ("PhoneData.txt");
   rec_num = 0;

   while (rec_num < num_entries){
      F << contactList[rec_num].name << " " << contactList[rec_num].number << " " << contactList[rec_num].notes  <<  " " << endl;
      rec_num++;
   }
   cout << "Phonebook stored." << endl;
   return;
}

// adds contact
void add_name(string name, string number, string notes){
   contactList[num_entries].name = name;
   contactList[num_entries].number = number;
   contactList[num_entries].notes = notes;
   num_entries++;
   return;
}

// finds contact
void retrieve_name(string name){
   for (int i = 0; i < num_entries; i++){
      if (toUpper(contactList[i].name) == toUpper(name)) {
         cout << "Phone Number: " << contactList[i].number << endl << "Notes: " << contactList[i].notes << endl;
         return;
      }
   }
   cout << "Name not found" << endl;
   return;
}

// updates contact info
void update_name(string name){
   string new_number;
   string new_notes;
   cout<<"New Phone Number"<<endl;
   cin>> new_number;
   cout<<"New Notes"<<endl;
   cin>> new_notes;
   for (int i = 0; i < num_entries; i++){
      if (toUpper(contactList[i].name) == toUpper(name)) {
         contactList[i].number = new_number;
         contactList[i].notes = new_notes;
         return;
      }
   }
}

// deletes contact
void delete_name(string name){
   int INDEX=0;
   for (int i = 0; i < num_entries; i++){
      if (toUpper(contactList[i].name) == toUpper(name)) {
         INDEX=i;
         for ( int j=INDEX; j < num_entries; j++ ){
            contactList[j].name = contactList[j+1].name;
            contactList[j].number = contactList[j+1].number;
            contactList[j].notes = contactList[j+1].notes;
         }
      }
   }
   return;
}

void listAllContacts() {
   int i = 0;
   while (i < num_entries) {
      cout << "-- " << contactList[i].name << " " << contactList[i].number << endl << "-- " << contactList[i].notes << endl << endl;
      i++;
   }
}

int main(){
   string name, number, notes;
   string FileName;
   char command;
   FileName = "PhoneData.txt";
   ReadFile ();
   cout << "Use \"e\" for enter, \"f\" for find, \"l\" for list, \"d\" for delete, \"u\" for update, \"s\" for send message, \"q\" to quit." << endl << "Command: ";
   cin >> command;
   while (command != 'q'){
      switch (command){
         case 'e': cin >> name; cout << "Enter Number: ";
                   cin >> number; cout << "Enter Notes: ";
                   cin.ignore(); getline(cin, notes);
                   add_name(name, number, notes); break;
         case 'f': cin >> name; retrieve_name(name); break;
         case 'l':
                   listAllContacts(); break;
         case 'u': cin>> name; update_name (name);break;
         case 'd' : cin>> name; delete_name (name); break;
      }
      cout << "\nCommand: "; cin >> command;
   }
   StoreFile();
   cout << "All set !";
   return 0;
}