need little help of bug fixers.

[vkash]

I know why it was wrong there when i return a class x data from operator+ to main then it is temporary just as it comes to main it is sent to operator= is called which is taking a temporary data this makes error(in some cases wrong deletion of data). other sources of error are deleting that memory which is even not initialized that's why i put tk function(to initialize if not initialized) .

I think my explanation is not fully correct (copy constructor copy data).


why returning by reference not work

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
#include<iostream>
using namespace std;
class x
{
    private:
    int i;
    int* p;

    public:
    x(int xi,int xp);
    x(const x&);
    ~x();
    void get() const;
    int geti() const ;
    int getp() const;
    x& operator=(const x&);
    x& operator+(const x&);
    void change(int ,int);
	void tk()
	{
		cout<<"tk\n";
		i =1;
		p=new int(0);
	}
};
static int m(0);
x::x(int xi=1,int xp=1)
{
	cout<<"constructor start..."<<xi<<endl;
	bool d(0);
	if((xi>1000)||(xp>1000)||(xi<0)||(xp<0))
	{
		cout<<"setting by default large data"<<xi<<xp<<" \n";
	d=1;
	}
	
    
    i=xi;
    p=new int(xp);
	if(d==1)
	{
		i=1;
		p=new int(1);
	}
	m++;
    cout<<"constructor  end..."<<m<<endl<<endl;
	
}
x::x(const x& xc)
{
    cout<<"copy constructor start ..."<<endl;
	//cout<<"going to copy in "<<i<<"  "<<*p<<endl;
	p=0;
    int it=xc.geti();
    int pt=xc.getp();
    this->change(it,pt);
	m++;
    cout<<"copy constructor  end  ..."<<endl;
}
static int j;
x::~x() 
{
	
    cout<<"destructor start..."<<i<<endl;
    delete p;
	j++;
    cout<<"destructor  end ..."<<j<<endl<<endl;
	
}
void x::get() const
{
    cout<<"void get() start ..."<<endl;
    cout<<"*******:   "<<i<<endl;
    cout<<"pointer:   "<<*p<<endl;
    cout<<"void get()  end ... "<<endl<<endl;
}
int x::geti() const
{
    return i;
}
int x::getp() const
{
	int a=*p;
    return a;
}
void x::change(int a,int b)
{
    cout<<"void change() start ..."<<endl;
    i=a;
    delete p;
    int*op=new int(b);
    p=op;
    cout<<"void change()  end  ..."<<endl;
}
x& x::operator=(const x& xn)
{
    cout<<"operator= start..."<<endl;
    int it=xn.i;
    int pt=xn.getp();
    change(it,pt);
    cout<<"operator= end ..."<<endl;
    return *this;
}
x& x::operator+(const x& xop)  //here returning by reference not work 
{
	cout<<"opearator+ start...\n";
    int itmp=this->geti()+xop.geti();
    int ptmp=this->getp()+xop.getp();
    //x* xreturn=new x(itmp,ptmp);
	x tr(itmp,ptmp);
	cout<<"operator+ end  ..."<<"\n";
    return tr;//x(itmp,ptmp);//*xreturn;
}
int main()
{
	{
    x x3;
	x x2(10,20);
    x x4(100,200);
    x3=(x4+x2);
    cout<<"result"<<endl;
    x3.get();
	}
	cout<<m<<"   "<<j<<endl;
	_CrtDumpMemoryLeaks();
	return 0;

}

It hangs in between execution.
I can't explain why returning by reference not work. Can you please explain?