Если bool name=false, то !name это true?

#include <iostream>
#include <list>
#include <algorithm>
#include <string>
using namespace std;
 
class person
   {
   private:
      string lastName;
      string firstName;
      long phoneNumber;
   public:
      person() :             // no-arg constructor
           lastName("blank"), firstName("blank"), phoneNumber(0L)
         {  }
                             // 3-arg constructor
      person(string lana, string fina, long pho) :
              lastName(lana), firstName(fina), phoneNumber(pho)
         {  }
      friend bool operator<(const person&, const person&);
      friend bool operator==(const person&, const person&);
      friend bool operator!=(const person&, const person&);
      friend bool operator>(const person&, const person&);
 
      void display() const   // display all data
         {
         cout << endl << lastName << ",\t" << firstName
              << "\t\tPhone: " << phoneNumber;
         }
 
      long get_phone() const // return phone number
         { return phoneNumber; }
   };
                             // overloaded == for person class
bool operator==(const person& p1, const person& p2)
   {
   return (p1.lastName == p2.lastName &&
           p1.firstName == p2.firstName ) ? true : false;
   }
                             // overloaded < for person class
bool operator<(const person& p1, const person& p2)
   {
   if(p1.lastName == p2.lastName)
      return (p1.firstName < p2.firstName) ? true : false;
   return (p1.lastName < p2.lastName) ? true : false;
   }
                             // overloaded != for person class
bool operator!=(const person& p1, const person& p2)
   { return !(p1==p2); }
                             // overloaded > for person class
bool operator>(const person& p1, const person& p2)
   { return !(p1<p2) && !(p1==p2); }
 
int main()
   {
   list<person> persList;    // list of persons
                             // iterator to a list of persons
   list<person>::iterator iter1;
                             // put persons in list
   persList.push_back( person("Deauville", "William", 8435150) );
   persList.push_back( person("McDonald", "Stacey", 3327563) );
   persList.push_back( person("Bartoski", "Peter", 6946473) );
   persList.push_back( person("KuangThu", "Bruce", 4157300) );
   persList.push_back( person("Wellington", "John", 9207404) );
   persList.push_back( person("McDonald", "Amanda", 8435150) );
   persList.push_back( person("Fredericks", "Roger", 7049982) );
   persList.push_back( person("McDonald", "Stacey", 7764987) );
 
   cout << "\nNumber of entries = " << persList.size();
 
   iter1 = persList.begin();  // display contents of list
   while( iter1 != persList.end() )
      (*iter1++).display();
 
// find person or persons with specified name (last and first)
   string searchLastName, searchFirstName;
   cout << "\n\nEnter last name of person to search for: ";
   cin >> searchLastName;
   cout << "Enter first name: ";
   cin >> searchFirstName;
                              //make a person with that name
   person searchPerson(searchLastName, searchFirstName, 0L);
                              //search for first match of names
   iter1 = find(persList.begin(), persList.end(), searchPerson);
   if( iter1 != persList.end() )  //find additional matches
      {
      cout << "Person(s) with that name is(are)";
      do
         {
         (*iter1).display();  //display match
         ++iter1;             //search again, one past match
         iter1 = find(iter1, persList.end(), searchPerson);
         } while( iter1 != persList.end() );
      }
   else
      cout << "There is no person with that name.";
 
// find person or persons with specified phone number
   cout << "\n\nEnter phone number (format 1234567): ";
   long sNumber;              //get search number
   cin >> sNumber;
                              //iterate through list
   bool found_one = false;
   for(iter1=persList.begin(); iter1 != persList.end(); ++iter1)
      {
      if( sNumber == (*iter1).get_phone() )  //compare numbers
         {
         if( !found_one )
            {
            cout << "Person(s) with that phone number is(are)";
            found_one = true;
            }
         (*iter1).display();  //display the match
         }
      }  //end for
   if( !found_one )
      cout << "There is no person with that phone number";
   cout << endl;
   return 0;
   }

if( !found_one )//то есть, если found_one==true...
{
            cout << "Person(s) with that phone number is(are)";
            found_one = true;//...то found_one присваивается true? Зачем, если переменная итак уже true?
 }