Question 1.2 Forward declaration • Write the following forward class declaration

Question

Question 1.2 Forward declaration

• Write the following forward class declarations for Parent and Child.

class Child; // forward statement that class "Child" exists

class Parent; // forward statement that class "Parent" exists

class Parent {

public:

Parent();

string getName() const;

void setName(string n);

void addChild(const Child &c);

int numChildren() const;

const vector& getChildren() const;

private:

string name;

vector children;

};

class Child {

public:

Child(string n, int a, const Parent &pt);

string getName() const;

int getAge() const;

const Parent* getParent() const;

private:

string name;

int age;

Parent p;

};

• The Parent and Child class mention each other, but do not do anything.

• The function bodies have not been written yet.

• In the Parent class, the reference to the vector for getChildren() is const because we do not want an external application to change somebody’s children.

• In the Child class, the pointer for getParent() is const because we do not want an external application to change somebody’s parent.

Explanation / Answer

#include<iostream>
#include<string>
#include<vector>

using namespace std;

class Child; // forward statement that class "Child" exists
             // forward statement that class "Parent" exists
class Parent {
public:
Parent(){
   name = "";
}
string getName() const {
   return name;
}
void setName(string n){
    name = n;
}
void addChild(const Child &c){
    children.push_back(c);
}
int numChildren() const{
    return children.size();
}
const vector<Child>& getChildren() const{
    return children;
}
private:
string name;
vector <Child>children;
};
class Child {
public:
Child(string n, int a, const Parent &pt){
    name = n;
    age = a;
    p.setName(pt.getName());
    vector<Child> b = pt.getChildren();
    vector<Child> c = p.getChildren();
    for (int i = 0; i< b.size(); i++){
        c.push_back(b[i]);
    }
   
}
string getName() const{
   return name;
}
int getAge() const{
    return age;
}
const Parent* getParent() const{
   return &p;
}
private:
string name;
int age;
Parent p;
};

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