How can I overload the + operator in C++ for a family vacation program?

[sxal96]

Hi, I'm having difficulty with this program in a textbook. The instructions are as follows:

Overload the + operator as indicated. Sample output for the given program:
First vacation: Days: 7, People: 3
Second vacation: Days: 12, People: 3

This is the code that follows

#include <iostream>
using namespace std;

class FamilyVacation{
   public:
      void  SetNumDays(int dayCount);
      void  SetNumPeople(int peopleCount);
      void  Print() const;
      FamilyVacation operator+(int moreDays);
   private:
      int   numDays;
      int   numPeople;
};

void FamilyVacation::SetNumDays(int dayCount) {
   numDays = dayCount;
   return;
}

void FamilyVacation::SetNumPeople(int peopleCount) {
   numPeople = peopleCount;
   return;
}

// FIXME: Overload + operator so can write newVacation = oldVacation + 5,
//        which adds 5 to numDays, while just copying numPeople.

/* Your solution goes here  */

void FamilyVacation::Print() const {
   cout << "Days: " << numDays << ", People: " << numPeople << endl;
   return;
}

int main() {
   FamilyVacation firstVacation;
   FamilyVacation secondVacation;

   cout << "First vacation: ";
   firstVacation.SetNumDays(7);
   firstVacation.SetNumPeople(3);
   firstVacation.Print();

   cout << "Second vacation: ";
   secondVacation = firstVacation + 5;
   secondVacation.Print();

   return 0;
}

I have to put my solution directly underneath where it asks for it, so I tried this but it sets the "People" value in the second vacation to 0.

FamilyVacation FamilyVacation::operator+(int moreDays){
   moreDays = numDays + 5;
}

Idk what to do so that the number of people doesn't change when I update numDays. Also, if I use anything involving "return" at the very end, it leads to an error. Any help/guidance would be appreciated.

 

[I like Serena]

Hi moofasa! Welcome to MHB! (Smile)

The FIXME comment says: "which adds 5 to numDays, while just copying numPeople."

However, in your solution 'numDays' is not changed. Instead 'moreDays' gets changed. But that's only a parameter that gets discarded afterwards.
Furthermore, 'numPeople' is not copied. (Worried)

 

[sxal96]

Hi moofasa! Welcome to MHB! (Smile)

The FIXME comment says: "which adds 5 to numDays, while just copying numPeople."

However, in your solution 'numDays' is not changed. Instead 'moreDays' gets changed. But that's only a parameter that gets discarded afterwards.
Furthermore, 'numPeople' is not copied. (Worried)

Thank you!

How would I copy numPeople? Anytime I try incorporating 'numPeople' into my solution, I get an error saying that numPeople isn't declared or that it could not be converted.

 

[I like Serena]

How would I copy numPeople? Anytime I try incorporating 'numPeople' into my solution, I get an error saying that numPeople isn't declared or that it could not be converted.

We need a new instance of FamilyVacation that we initialize with the proper values.
We can do that by declaring [m]FamilyVacation result;[/m], initializing it, and returning it at the end.

 

[sxal96]

We need a new instance of FamilyVacation that we initialize with the proper values.
We can do that by declaring [m]FamilyVacation result;[/m], initializing it, and returning it at the end.

I don't really understand operator overloading at all but this is my attempt that led to an error

class FamilyVacation result{
   public: 
      void result(int peopleCount, numPeople);
   private:
};

void FamilyVacation FamilyVacation::result(int peopleCount, int numPeople){
   peopleCount = numPeople;
   return;
}

FamilyVacation FamilyVacation::operator+(int moreDays){
   moreDays = numDays + 5;
}

 

[I like Serena]

I don't really understand operator overloading at all but this is my attempt that led to an error

FamilyVacation FamilyVacation::operator+(int moreDays){
   moreDays = numDays + 5;
}

Consider the function [m]FamilyVacation FamilyVacation:perator+(int moreDays)[/m].
It has 'moreDays' as input.
Changing that input won't have any effect.

More importantly, the function is supposed to return a [m]FamilyVacation[/m].
As it is now, it's not returning anything, which is already an error condition.

It should be something like:

FamilyVacation FamilyVacation::operator+(int moreDays){
   FamilyVacation result;
   ...
   return result;
}