How to pass an object(type a) to a private object(type a) of another object(type b) through function of friend - c++

Question

#include <iostream>
#include <vector>
using namespace std;
class Flight;
class Time {
private :
int hour;
int minute;
public :
Time(int hour,int minute){
this->hour = hour;
this->minute = minute;
};
int getHour(){
return hour;
}
int getMinute(){
return minute;
}
};
class Passenger{
private:
string name;
int age;
public :
Passenger(string name , int age){
this->name = name;
this->age = age;
}
void printDetails(){
cout << "Name: " << name << "\t";
cout << "Age: " << age <<"\t";
}
friend void addPassenger(Passenger *p,int num,Flight f);
friend Flight;
};
class Flight {
private :
string id;
string destination;
Time *depart;
Time *arrival;
vector<Passenger> passengerList;
Passenger *pass;
public :
Flight(string id, string destination, Time *t, Time *a){
this->id = id;
this->destination = destination;
depart = t;
arrival = a;
id = 3;
};
void printInfo(){
cout<< "Flight Number : " << id << endl;
cout<< "Destination : " << destination << endl;
cout<< "Desparture : " << depart->getHour() << ":" << depart->getMinute()<< endl;
cout<< "Arrival : " << arrival->getHour() << ":" << arrival->getMinute() << endl;
}
void printList(){
cout << pass->name[0];
}
friend class Passenger;
friend void addPassenger(Passenger *p,int num,Flight f);
};
void addPassenger(Passenger *p,int num,Flight f){
// for(int i=0;i<num;i++){
// f.passengerList.push_back(p[i]);
f.pass->name = p->name;
// }
}
int main(){
int num_passenger;
int temp_age;
string temp_name;
vector<int> passenger_age;
vector<string> passenger_name;
Time t(2,4);
Time t2(2,3);
Flight ff("3","4",&t,&t2);
cout<< "Enter the number of passenger" << endl;
cin>> num_passenger;
cout<< endl;
Passenger *pas[num_passenger];
for(int i=0;i < num_passenger; i++){
cout<< "Enter the name of adult "<< i+1 << endl;
cin>> temp_name;
passenger_name.push_back(temp_name);
cout<< "Enter the age of adult "<< i+1 << endl;
cin>> temp_age;
passenger_age.push_back(temp_age);
}
for(int p=0; p < num_passenger; p++){
pas[p] = new Passenger(passenger_name[p],passenger_age[p]);
}
addPassenger(*pas,2,ff);
ff.printList();
return 0;
}
I need to pass array object of Passenger Class into private array object of Passenger Class that inside object of Flight Class through function addPassenger.
Everything compile fine, but I can't get printList(object Flight) work, it simply jumps out and terminates the console.
Sorry it quite complicated due to requirement of project.
Hope to have some helps, Thanks.

Answer 1

Problem 1
The main problem is at line
f.pass->name = p->name;
The source of the problem is that the member variable pass of Flight is not initialized properly and then you go on to use f.pass as though it is a valid pointer.
Problem 2
The function addPassenger takes a Flight object as input. When you call the function, the function gets a copy of the original Flight object. Any changes made to the Flight object in addPassenger are to the local copy, not the object from main.
With the following changes, I was able to run your program without any problem.
Changed the member of variable of Flight to:
string id;
string destination;
Time *depart;
Time *arrival;
vector<Passenger> passengerList;
Removed the member varible pass.
Changed the signature of addPassenger to.
void addPassenger(std::vector<Passenger> const& plist, Flight& f);
and changed its implementation to
void addPassenger(std::vector<Passenger> const& plist, Flight& f)
{
for(auto& p : plist ){
f.passengerList.push_back(p);
}
}
Changed the implementation of Flight::printList to:
void printList(){
for(auto& p : passengerList ){
cout << p.name << endl;
}
}
Changed the type of pas in main to:
std::vector<Passenger> pas;
Other things needed to be changed to account for these changes. Here's the complete program:
#include <iostream>
#include <vector>
using namespace std;
class Flight;
class Time {
private :
int hour;
int minute;
public :
Time(int hour,int minute){
this->hour = hour;
this->minute = minute;
};
int getHour(){
return hour;
}
int getMinute(){
return minute;
}
};
class Passenger{
private:
string name;
int age;
public :
Passenger(string name , int age){
this->name = name;
this->age = age;
}
void printDetails(){
cout << "Name: " << name << "\t";
cout << "Age: " << age <<"\t";
}
friend void addPassenger(std::vector<Passenger> const& plist, Flight& f);
friend Flight;
};
class Flight {
private :
string id;
string destination;
Time *depart;
Time *arrival;
vector<Passenger> passengerList;
public :
Flight(string id, string destination, Time *t, Time *a){
this->id = id;
this->destination = destination;
depart = t;
arrival = a;
id = 3;
};
void printInfo(){
cout<< "Flight Number : " << id << endl;
cout<< "Destination : " << destination << endl;
cout<< "Desparture : " << depart->getHour() << ":" << depart->getMinute()<< endl;
cout<< "Arrival : " << arrival->getHour() << ":" << arrival->getMinute() << endl;
}
void printList(){
for(auto& p : passengerList ){
cout << p.name << endl;
}
}
friend class Passenger;
friend void addPassenger(std::vector<Passenger> const& plist, Flight& f);
};
void addPassenger(std::vector<Passenger> const& plist, Flight& f)
{
for(auto& p : plist ){
f.passengerList.push_back(p);
}
}
int main(){
int num_passenger;
int temp_age;
string temp_name;
vector<int> passenger_age;
vector<string> passenger_name;
Time t(2,4);
Time t2(2,3);
Flight ff("3","4",&t,&t2);
cout<< "Enter the number of passenger" << endl;
cin>> num_passenger;
cout<< endl;
std::vector<Passenger> pas;
for(int i=0;i < num_passenger; i++){
cout<< "Enter the name of adult "<< i+1 << endl;
cin>> temp_name;
passenger_name.push_back(temp_name);
cout<< "Enter the age of adult "<< i+1 << endl;
cin>> temp_age;
passenger_age.push_back(temp_age);
}
for(int p=0; p < num_passenger; p++){
pas.push_back(Passenger(passenger_name[p],passenger_age[p]));
}
addPassenger(pas, ff);
ff.printList();
return 0;
}
See it working at http://ideone.com/Chttoe.