OperatorOverload, C++ (gcc)

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//g++  7.4.0
//operator overloading: input,output, assignment, conversion & subscript
//this code is created by Rezaul Hoque on September 01,2021;contact: jewelmrh@yahoo.com

//note: codes shared by Rezaul Hoque on rextester are not for sale; they are created and shared to facilitate the algorithm learning process; many like Hoque use this platform to practice programming ;Rezaul hopes his contribution helps others to fine tune their learning;

#include <iostream>
namespace Garden{
class Vegetable{
friend std::istream & operator>>(std::istream& istr,Vegetable& in);//input operator
friend std::ostream & operator<<(std::ostream& ostr ,const Vegetable& print);//output operator

int l, b,m;

public:
Vegetable (){}//default constructor
Vegetable (int vl,int vb){ l=vl; b=vb;}//Vegetable(int,int ) constructor
Vegetable (const Vegetable& v){l=v.l; b=v.b;}//copy constructor

Vegetable& operator=(const Vegetable& eq){ l=eq.l; b=eq.b; return *this;}//assignment operator
int& operator[](int);//subscript operator
operator double();//conversion operator

int  area(){return l*b;}
};

std::istream & operator>>(std::istream & istr,Vegetable& in)
{
std::cout<<"\nLength: \n"; istr>>in.l;
std::cout<<"\nBreadth:\n"; istr>>in.b;
return istr;
}

std::ostream & operator<<(std::ostream & ostr,const Vegetable& print)
{
ostr<<"\nLength:\n"<<print.l<<"\nBreadth:\n"<<print.b;
return ostr;
}
int& Vegetable::operator[](int i){
if (i==1) return l;
if (i==2) return b;
if(i==3) return m=area();
std::cerr<<"Index out of range.\n";
exit(0);
}
Vegetable:: operator double()
{
return double(l*b);
}

}

int main(){
Garden::Vegetable x,y,z;
std::cin>>x>>y;//input operator is called
std::cout<<"\nx:\n"<<x<<"\ny:\n"<<y;//output operator is called
z=y;//assignment operator is called
std::cout<<"\nArea:\n"<<"For x:\n";
std::cout<<double(x.area());//conversion operator is called
std::cout<<"\nFor y:\n"<<double(z.area());
std::cout<<"\nUse of subscript operator(index 1 for lengtg,2 for breadth and 3 for area):\n";
std::cout<<"x[1]= "<<x[1]<<";\n"<<"x[2]= "<<x[2]<<";\n"<<"x[3]= "<<x[3]<<";\n";//subscript operator is called
std::cout<<"y[1]= "<<z[1]<<";\n"<<"y[2]= "<<z[2]<<";\n"<<"y[3]= "<<z[3]<<";\n"<<"y[4]= "<<y[4];
return 0;
}

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Compilation time: 0.42 sec, absolute running time: 0.15 sec, cpu time: 0.01 sec, memory peak: 5 Mb, absolute service time: 0,66 sec