Here is the code I have
#include<iostream>
using namespace std;
void push_t(int j)
//---------------------------------------------------
// Accepts a value and pushes it onto the stack top
// Precondition: if keyset = 0 the deque does not yet exits
// deque is a structure with int j for data
// Postcondition: values are pushed onto the stack and
// the value of stackpointer is incremented
//If the structure does not exist it is created.
//in which case the top and bottom are the same cell
//----------------------------------------------------
{
if (keyset==0){keyset=1;//create deque
Top =new bx;
Top->prior=NULL;
Top->next=NULL;
Top->key=j;
Bottom=Top;
}//push onto top
else{
Topx =new bx;
Topx->key=j;
Topx->next=NULL;
Topx->prior=NULL;
Top->prior=Topx;
Topx->next=Top;
Top=Topx;
}
}
//end of push_t
//---------------------------------
void pop_t(int &n,int &r)
//---------------------------------------------------
// Pops a number off the top of the queue and returns it
// Precondition:the deque may or may not exist
// Postcondition: values are popped off the stack and
// if empty "empty is returned and r=1 is returned.
//----------------------------------------------------
{r=0;
if (keyset==0){cout<<"Empty"<<endl<<endl;n=NULL;r=1; return;}//empty deque
if(Top->next==NULL)// One item only in deque
{
keyset=0;//reset deque to empty
n=Top->key;
delete Top;
return;
}
bxx=Top->next;
n=Top->key;
delete Top;
Top=bxx;
Top->prior=NULL;
return;
}//end of pop_t
//----------------------------------------------------
void push_b(int j)
//---------------------------------------------------
// Accepts a value and pushes it onto the bottom of the deque
// Precondition: deque is a structure with int j for data
// if keyset = 0 the deque does not yet exist
// Postcondition: values are pushed onto the bottom of the deque
// If the structure does not exist it is created.
// in which case the top and bottom are the same cell
//----------------------------------------------------
{
int * Top;
if (keyset==0){
keyset=1;//create deque
Top =new bx;
Top->key=j;
Top->prior=NULL;
Top->next=NULL;
Bottom=Top;
}
//push onto bottom
else{
Bottomx =new bx;
Bottomx->next=NULL;
Bottomx->prior=NULL;
Bottomx->key=j;
Bottom->next=Bottomx;
Bottomx->prior=Bottom;
Bottom=Bottomx;
}
}
//end of push_b
//-------------------------------------------------------
void pop_b(int &n, int &r)
//---------------------------------------------------
// Pops number off the the bottom of the deque
// Precondition: the structure may or may not exist
// Postcondition: values are popped off the stack and
// if it does not exist r=1="empty" is returned
//
//----------------------------------------------------
{
r=0;
if (keyset==0){cout<<"Empty"<<endl<<endl;n=NULL;r=1; return;}//empty deque
if(Bottom->prior==NULL)// One item only in deque
{
keyset=0;//reset deque to empty
n=Bottom->key;
delete Bottom;
return;
}
bxx=Bottom->prior;
n=Bottom->key;
delete Bottom;
Bottom=bxx;
Bottom->next=NULL;
return;
}//end of pop_b
//--------------------------------------------------
//---------------------------------------------------
void display_deque()
//---------------------------------------------------
// Prints the contents of the deque in order top to bottom
// Precondition: None.
// Postcondition: No change. If the deque is empty the message
// "Empty" is printed.
//----------------------------------------------------
{cout<<"Data: "<<endl<<endl;
if (keyset==0){cout<<"Empty"<<endl<<endl; return;}//empty deque
// cout<<Top->key<<endl;
bxx=Top;
while(bxx->next!=NULL){
cout<<bxx->key<<endl;
bxx=bxx->next;
} cout<<bxx->key<<endl<<"End"<<endl<<endl;
return;
}//end of display_deque
//------------------------------------------------------
//----------------------------------------
//constructor - sets deque stack to zero
//initialze variables
//-----------------------------------------
int dq()
{
keyset=0;
int j=0;
Topx=NULL;
Bottomx=NULL;
}//end constructor
//--------------------------------------
//end of deque functionsI have to create a double ended queue. I got this code to work with, but I dont know how to declare the variables on this. Especially when you have something like "Top->key=j;" Just looking for some ideas to get started. Thanks.
