Where is the mistake!!!

#include

using namespace std;

struct node

{

int info;

node *forw;

node*back;

};

class sll

{

private:

node *head;

public:

sll(){head=new node;

head->forw=head;

head->back=head;

}

void AddNode (int);

void Traverse();

void AddBefore(int,int);

};

void sll::AddNode (int val)

{

node *newNode= new node;

newNode->info=val;

newNode->forw=head;

newNode->back=head->back;

head->back->forw=newNode;

head->back=newNode;

}

void sll::Traverse()

{

if (head->forw==head)

cout<<" The list is empty";

for (node * curr=head->forw ;curr!=head; curr=curr->forw){

cout<info<<" , ";}

}

void sll::AddBefore(int k , int item)

{

node * curr=head->forw;

while(curr!=head){

if(curr->info==k){

break;

curr=curr->forw;}

}

if(curr==head)

cout<<"is empty";

else{

node*p=new node;

p->info=item;

p->back=curr->forw;

p->forw=curr;

curr->forw->back=p;

curr->back=p;

}

}

int main()

{

sll s;

int inf, ch ;

int k,item;

while(1)

{

cout<<" choice case";

cin>>ch;

switch(ch)

{

case 1:

cout<<" Put info/value to Add: ";

cin>>inf;

s.AddNode(inf);

break;

case 2:cout<<" Linked List Values: ";

s.Traverse();

break;

case 3:

cout<<"AddBefore:";

cin>>k>>item;

s.AddBefore( k ,item );

break;

default: exit(0);

}

}

return 0;

}