Friend function ex1

 #include<iostream>

using namespace std;

class rectangle

{

double length;

public:

friend void printlength(rectangle R);

void setlength(double len);

};

void rectangle::setlength(double len)

{

length=len;

}

void printlength(rectangle rectangle)

{

cout<<"length of rectangle :"<<R.length<<endl;

}

int main()

{

rectangle R;

R.setlength(10.0);

printlength(R);

return 0;

}