Sep 29, 2013 at 6:49pm UTC
Here is my program.. I am unable to concatenate the 2 linked lists using operator overloading. I have got the output of the concatenation once and then again i am not getting it. it is compiling but stucks in run time. Please help me.
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#include <iostream>
#include <string>
using namespace std;
class LinkedList
{
public :
struct Node
{
string value;
Node *next;
}*p;
LinkedList()
{
p = NULL;
}
/*~LinkedList()
{
delete p;
}*/
void printAll();
void addLast(string name);
void addFirst(string name);
void removeFirst();
void removeLast();
void getFirst();
void getLast();
LinkedList operator +(const LinkedList &l);
};
LinkedList LinkedList::operator +(const LinkedList &l)
{
LinkedList l1 = *this ;
Node *tmp= l1.p;
while (tmp!=NULL)
{
tmp=tmp->next;
}
tmp->next = l.p;
return l1;
}
void LinkedList::getFirst()
{
if (p!=NULL)
{
cout<<"The first node in the list is: " <<p->value<<endl;
}
}
void LinkedList::getLast()
{
Node *tmp=p;
while (tmp!=NULL)
{
tmp=tmp->next;
}
if (tmp->next==NULL)
{
cout<<"The last node in the list is: " <<tmp->value<<endl;
}
}
void LinkedList::printAll()
{
if (p==NULL)
{
cout<<"There are no nodes in the list" <<endl;
return ;
}
else
{
Node *tmp = p;
cout<<endl<< "The nodes in the list are: " ;
while (tmp!=NULL)
{
cout << tmp->value<<" " ;
tmp=tmp->next;
}
}
}
void LinkedList::addFirst(string name)
{
if (name.length()>4)
{
cout<<" The string having more than 4 characters could not be inserted into the list" <<endl;
return ;
}
else
{
Node* tmpFirst = new Node;
tmpFirst->value=name;
tmpFirst->next=p;
p=tmpFirst;
}
}
void LinkedList::addLast(string name)
{
if (name.length()>4)
{
cout<<" The string having more than 4 characters could not be inserted into the list" <<endl;
return ;
}
else
{
Node *tmpLast = new Node;
tmpLast->value=name;
tmpLast->next=NULL;
if (p==NULL)
p=tmpLast;
else
{
Node *tmp=p;
while (tmp->next!=NULL)
{
tmp=tmp->next;
}
tmp->next=tmpLast;
}
}
}
void LinkedList::removeFirst()
{
if (p==NULL)
{
cout<<"The list is empty" <<endl;
return ;
}
else
{
Node *tmp=p;
p=p->next;
tmp->next=NULL;
delete tmp;
}
}
void LinkedList::removeLast()
{
if (p==NULL)
return ;
else
{
Node *tmp=p;
Node *tmp1=p;
while (tmp->next!=NULL)
{
tmp=tmp->next;
}
while (tmp1->next!=tmp)
{
tmp1=tmp1->next;
}
tmp1->next=NULL;
}
}
int main()
{
LinkedList list1;
LinkedList list2;
LinkedList list3;
list1.addFirst("asda" );
list2.addLast("fdgs" );
list1.printAll();
list2.printAll();
list1+list2;
list1.printAll();
}
Last edited on Sep 29, 2013 at 7:54pm UTC
Sep 29, 2013 at 7:45pm UTC
The loop on line 41 causes the iteration node to be null once the loop ends, so the assignment on line 45 dereferences a null pointer. Try to come up with a condition for the loop that will fix this.
Sep 29, 2013 at 8:09pm UTC
it worked Helios.. In while statement i kept while(tmp->next!=NULL) and it worked :)
Sep 29, 2013 at 8:24pm UTC
when i add the copy constructor to the same code, its stucking at the run time. I dnt understand why
#include <iostream>
#include <string>
using namespace std;
class LinkedList
{
public:
struct Node
{
string value;
Node *next;
}*p;
LinkedList()
{
p = NULL;
}
/*~LinkedList()
{
delete p;
}*/
void printAll();
void addLast(string name);
void addFirst(string name);
void removeFirst();
void removeLast();
void getFirst();
void getLast();
LinkedList operator+(const LinkedList &l);
LinkedList(const LinkedList &l);
};
LinkedList::LinkedList(const LinkedList &l)
{
Node* tmp = l.p;
while (tmp!=NULL)
{
Node* tmpcopy = new Node;
tmpcopy->value = tmp->value;
tmp = tmp->next;
}
}
LinkedList LinkedList::operator+(const LinkedList &l)
{
LinkedList l1 = *this;
Node *tmp = l1.p;
while(tmp->next!=NULL)
{
tmp=tmp->next;
}
tmp->next = l.p;
return l1;
}
void LinkedList::getFirst()
{
if(p!=NULL)
{
cout<<"The first node in the list is: "<<p->value<<endl;
}
}
void LinkedList::getLast()
{
Node *tmp=p;
while(tmp!=NULL)
{
tmp=tmp->next;
}
if(tmp->next==NULL)
{
cout<<"The last node in the list is: "<<tmp->value<<endl;
}
}
void LinkedList::printAll()
{
if(p==NULL)
{
cout<<"There are no nodes in the list"<<endl;
return;
}
else
{
Node *tmp = p;
cout<<endl<< "The nodes in the list are: ";
while(tmp!=NULL)
{
cout << tmp->value<<" ";
tmp=tmp->next;
}
}
}
void LinkedList::addFirst(string name)
{
if(name.length()>4)
{
cout<<" The string having more than 4 characters could not be inserted into the list"<<endl;
return;
}
else
{
Node* tmpFirst = new Node;
tmpFirst->value=name;
tmpFirst->next=p;
p=tmpFirst;
}
}
void LinkedList::addLast(string name)
{
if(name.length()>4)
{
cout<<" The string having more than 4 characters could not be inserted into the list"<<endl;
return;
}
else
{
Node *tmpLast = new Node;
tmpLast->value=name;
tmpLast->next=NULL;
if(p==NULL)
p=tmpLast;
else
{
Node *tmp=p;
while(tmp->next!=NULL)
{
tmp=tmp->next;
}
tmp->next=tmpLast;
}
}
}
void LinkedList::removeFirst()
{
if(p==NULL)
{
cout<<"The list is empty"<<endl;
return;
}
else
{
Node *tmp=p;
p=p->next;
tmp->next=NULL;
delete tmp;
}
}
void LinkedList::removeLast()
{
if(p==NULL)
return;
else
{
Node *tmp=p;
Node *tmp1=p;
while(tmp->next!=NULL)
{
tmp=tmp->next;
}
while(tmp1->next!=tmp)
{
tmp1=tmp1->next;
}
tmp1->next=NULL;
}
}
int main()
{
LinkedList list1;
LinkedList list2;
LinkedList list3;
LinkedList list4;
list1.addFirst("asda");
list2.addLast("fdgs");
list1.printAll();
list2.printAll();
list4 = list2;
list4.printAll();
list3 = list1+list2;
list3.printAll();
}