overloading operator + to add 2 dynamic arrays

[lulu girl]

hey guys
so am trying to study how to overload an operator but i keep getting this error

HEAP CORRUPTION DETECTED

this is my code...

#include<iostream>
using namespace std;

class ListType
{
	int size,length,*list;
public:
	ListType(int S)
{
	if (S<0)
		S=100;
	length=0;
	size=S;
	list=new int [S];
}


~ListType()
{
	delete []list;
}


ListType operator+ (ListType obj1)
{
	int k=0;
	ListType Temp;
	delete []Temp.list;
	Temp.size=size+obj1.size;
	Temp.length=length+obj1.length;	
	Temp.list=new int [size];

	for(int i=0;i<size;i++)
		Temp.list[k++]=list[i];
	for(int i=0;i<obj1.size;i++)
		Temp.list[k++]=obj1.list[i];
return Temp;
	}
void ListType::insert(int x)
{
	if(length==size)
		cout<<"invalid, The list is full"<<endl;
	else
		list[length]=x;
	length++;
}
};
void main()
{
	ListType obj1(4),obj2(3),obj3;
	obj1.insert(6);
	obj1.insert(44);
	obj2.insert(6);
	obj3=obj1+obj2;
}

can anyone please help me??? what does that error mean??? why does it appear??
what can i do to fix this error?

thanks so much in advance ^_^

[LB]

	ListType Temp;
	delete []Temp.list;

Temp was default constructed. You have not defined your default constructor to do anything, so Temp.list points to nothing, which you promptly delete[]

[lulu girl]

ooh actually the constructor is default i just forgot to put it

	ListType(int S=100)
{
	if (S<0)
		S=100;
	length=0;
	size=S;
	list=new int [S];
}

but i tried removing
delete []Temp.list;

then this message appeared

heap corruption detected

what does that mean?!?!
i googled it but didn't really understand!!

[vlad from moscow]

You did not define the copy assignement operator. So you have 1)leak of memory 2) heap corruption.

Here the copy assignment operator is used


obj3=obj1+obj2;

[lulu girl]

#include<iostream>
using namespace std;

class ListType
{
	int size,length,*list;
public:
	ListType(int S=100)
{
	if (S<0)
		S=100;
	length=0;
	size=S;
	list=new int [S];
}


~ListType()
{
	delete []list;
}


ListType  operator+ (ListType obj1)
{
	int k=0;
	ListType Temp;
	delete []Temp.list;
	Temp.size=size+obj1.size;
	Temp.length=length+obj1.length;	
	Temp.list=new int [Temp.size];

	for(int i=0;i<length;i++)
	Temp.list[k++]=list[i];
	for(int i=0;i<obj1.length;i++)
	Temp.list[k++]=obj1.list[i];
return Temp;
	}

ListType operator= (ListType obj)
{
	delete []list;
	size=obj.size;
	length=obj.length;
	for(int i=0;i<length;i++)
		list[i]=obj.list[i];
	
return *this;	
}
void ListType::insert(int x)
{
	if(length==size)
		cout<<"invalid, The list is full"<<endl;
	else
		list[length]=x;
	length++;
}

};
void main()
{
	ListType obj1(4),obj2(3),obj3;
	obj1.insert(6);
	obj1.insert(44);
	obj2.insert(6);
	obj3=obj1+obj2;
}

ok so i edited it
now it works fine but at the end of execution it tells me that the program stopped working O.o

why is that?!?!

[vlad from moscow]

Where are you coping elements of obj.list? You deleted already the original list. You shall allocate memory anew.

ListType operator= (ListType obj)
{
	delete []list;
	size=obj.size;
	length=obj.length;
	for(int i=0;i<length;i++)
		list[i]=obj.list[i];
	
return *this;	
}

[lulu girl]

thank you soooooo much it works now ^_^