Example of Friend function (1)

#include<iostream>
using namespace std;
class Rectangle
{
private:
    int height,weight ;
public:
    void getValue(int ,int );
    int area()
    {

        return height*weight;

    }

};
void Rectangle::getValue(int a,int b)
{
    height=a;
    weight=b;
}
class Cost
{
private:
    int tk;
public:
    void getvalue(int c)
    {
        tk=c;
    }
    int totalCost(Rectangle A)
    {
        return tk*A.area();
    }

};

int main()
{
    int a,b;
    cin>>a>>b;
    Rectangle rct;
    rct.getValue(a,b);
    cout<< "Total area = "<<rct.area()<<endl;

    int i;
    Cost cst;
    cout<<"enter cost per meter:"<<endl;
    cin>>i;
    cst.getvalue(i);
    cout<<"Total cost :"<<endl;
    cout<<cst.totalCost(rct);




    return 0;
}

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