Question : C++ Programming - error 2065 Program Email Address

#include <iostream>
#include <string>
#include <vector>
using namespace std;
 
vector<string> addresses;
 
string str1 = "[email protected]";
string str2 = "[email protected]";
string str3 = "[email protected]";
string str4 = "[email protected]";
string str5 = "[email protected]";
string str6 = "[email protected]";
string str7 = "[email protected]m";

bool processMenu() {
 cout << endl <<"What would you like to do?" << endl;
 cout << "1. Enter an email address. " << endl;
 cout << "2. Search for an email address. " << endl;
 cout << "3. List all email addresses. " << endl;
 cout << "4. Delete an email address. " << endl;
 cout << "5. Exit program. " << endl;
      
 char choice;
 cin >> choice;
      
 if(choice == '1'){
  cout << "You chose option #1." << endl;
cout << "Please enter the address: ";
string address;
cin>> address;
addresses.push_back(address);
processMenu();
                      
 }else if(choice == '2')
{
                      
 cout << "You chose option #2." << endl; //Search email addresses
   processMenu();
                      

            cout << "You chose option #3." << endl;
            cout << "Listing addresses. " << endl;
            for(int i = 0; i << addresses.size(); i++)
            {
              cout << "Email Address # " << i + 1 << ": " << addresses << endl;
            }
            processMenu();

            
                  {
                    cout << "Email Address # " << i + 1 << ": " << addresses << endl;
                      processMenu();
                  }
             }else if(choice == '4'){
                       cout << "You chose option #4." << endl;
                       //
                       processMenu();
           }else if(choice == '5'){
                     cout << "You chose option #5." << endl;
                     cout << "Exiting the program." << endl;
             
                     return 1;
                     
             }else{
                     return false;
           }
             return true;
      }
      
      int main()
      {
          char answer;
      
          cout << "Email storage program." << endl << endl;
      
          while (!processMenu()) {
                cout << "Sorry, that was an invalid choice." << endl;
                cout << "Please try again." << endl << endl;
          }
          cout << endl << "Thank you for using the program." << endl;
      
          system("pause");
          return 0;
      }

Answer : C++ Programming - error 2065 Program Email Address

I do not know why you need h-file, but if you will make it, then you will need to add:
#include "header_file_name.h". And in this h-file you may have only function signatures:
void display();