#!/bin/sh
# This is a shar archive.
# The rest of this file is a shell script which will extract:
#
# 7_6_app.c 7_6_apph.c 7_6_clear.c 7_6_cons1.c 7_6_cons2.c 7_6_dest.c 7_6_getn.c 7_6_getp.c 7_6_ins.c 7_6_insh.c 7_6_next.c 7_6_prev.c 7_6a.h 7_6b.h 7_6c.c 7_6d.c 7_6e.c 7_6f.h 7_6g1.gc 7_6g2.gc 7_6gI1.gc 7_6gI2.gc all.c makefile tst.c tst.cmp
#
# To extract the files from this shell archive file simply
# create a directory for this file, move the archive file
# to it and enter the command
#
#	sh filename
# 
# The files will be extracted automatically.
# Note: Do not use csh.
#
# Archive created: Mon Jul 30 23:10:43 EDT 1990
#
echo x - 7_6_app.c
sed 's/^X//' > 7_6_app.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Append an entry at the end of the list.
// This is the same as dlist::insert() except
// that dlist::last is adjusted afterwards.
void dlist::append(ent a)
{
    this->insert(a);
    last = last->next;
}
!EOF!
ls -l 7_6_app.c
echo x - 7_6_apph.c
sed 's/^X//' > 7_6_apph.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Append an entry after the
// current location of the list.
// If curr is not set, append at
// the end of the list.
void dlist::appendhere(ent a)
{
    if (curr)
	curr->append(new dlink(a));

    else
	this->append(a);
}
!EOF!
ls -l 7_6_apph.c
echo x - 7_6_clear.c
sed 's/^X//' > 7_6_clear.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// clear the list
void dlist::clear()
{
    dlink *l = last;
    if (!l) return;

    do  {
	dlink *ll = l;
	l = l->next;
	delete ll;
    } while (l != last);

    last = 0;
}
!EOF!
ls -l 7_6_clear.c
echo x - 7_6_cons1.c
sed 's/^X//' > 7_6_cons1.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
dlist::dlist()
{
    last = curr = 0;
}
!EOF!
ls -l 7_6_cons1.c
echo x - 7_6_cons2.c
sed 's/^X//' > 7_6_cons2.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
dlist::dlist(ent a)
{
    curr = 0;
    last = new dlink(a);
    last->next = last->prev = last;
}
!EOF!
ls -l 7_6_cons2.c
echo x - 7_6_dest.c
sed 's/^X//' > 7_6_dest.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// get rid of the list
dlist::~dlist()
{
    clear();
}
!EOF!
ls -l 7_6_dest.c
echo x - 7_6_getn.c
sed 's/^X//' > 7_6_getn.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Get the next entry from a list,
// removing it afterwards.
// curr is left alone.
int dlist::getnext(ent &a)
{
    if (!last)
	return 0;

    // choose the link to remove
    dlink *f;
    if (curr)
        if (curr == last)
	    {
	    curr = 0;
	    return 0;
	    }
	
	else
	    f = curr->next;

    else
	f = last->next;

    a = f->e;

    // remove f from the list
    if (f == last)
	last = 0;

    else
	f->remove();

    delete f;
    return 1;
}
!EOF!
ls -l 7_6_getn.c
echo x - 7_6_getp.c
sed 's/^X//' > 7_6_getp.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Get the previous entry from a list,
// removing it afterwards
int dlist::getprev(ent &a)
{
    if (!last)
	return 0;

    // choose the link to remove
    dlink *f;
    if (curr)
	if (curr == last->prev)
	    {
	    curr = 0;
	    return 0;
	    }

	else
	    f = curr->prev;

    else
	f = curr = last;

    a = f->e;

    // remove f from the list
    if (f == last)
	last = 0;

    else
	f->remove();

    delete f;
    return 1;
}
!EOF!
ls -l 7_6_getp.c
echo x - 7_6_ins.c
sed 's/^X//' > 7_6_ins.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// insert an entry at the beginning of the list
void dlist::insert(ent a)
{
    if (last)
	last->next->insert(new dlink(a));

    else
	{
	last = new dlink(a);
	last->next = last->prev = last;
	}
}
!EOF!
ls -l 7_6_ins.c
echo x - 7_6_insh.c
sed 's/^X//' > 7_6_insh.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Insert an entry before the
// current location of the list.
// If curr is not set, insert at
// the beginning of the list.
void dlist::inserthere(ent a)
{
    if (curr)
	curr->insert(new dlink(a));

    else
	this->insert(a);
}
!EOF!
ls -l 7_6_insh.c
echo x - 7_6_next.c
sed 's/^X//' > 7_6_next.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Get the next entry from a list,
// moving curr forward.
int dlist::next(ent &a)
{
    if (!last)
	return 0;

    // move curr forward, possibly to
    // the beginning or end of the list.
    if (curr)
	if (curr == last)
	    {
	    curr = 0;
	    return 0;
	    }

	else
	    curr = curr->next;

    else
	curr = last->next;

    a = curr->e;
    return 1;
}
!EOF!
ls -l 7_6_next.c
echo x - 7_6_prev.c
sed 's/^X//' > 7_6_prev.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Get the previous entry from a list,
// moving curr backwards.
int dlist::prev(ent &a)
{
    if (!last)
	return 0;

    // move curr backwards, possibly to
    // the beginning or end of the list.
    if (curr)
	if (curr == last->next)
	    {
	    curr = 0;
	    return 0;
	    }

	else
	    curr = curr->prev;

    else
	curr = last;

    a = curr->e;
    return 1;
}
!EOF!
ls -l 7_6_prev.c
echo x - 7_6a.h
sed 's/^X//' > 7_6a.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
typedef void *ent;
!EOF!
ls -l 7_6a.h
echo x - 7_6b.h
sed 's/^X//' > 7_6b.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
class dlink
{
    friend class dlist;
    dlink *next;
    dlink *prev;
    ent e;

    dlink(ent a, dlink *n = 0, dlink *p = 0)
    { e = a; next = n; prev = p; }

    void insert(dlink *n);
    void append(dlink *n);
    void remove();

    ~dlink() { remove(); }
};
!EOF!
ls -l 7_6b.h
echo x - 7_6c.c
sed 's/^X//' > 7_6c.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// insert a dlink in front of this one
void dlink::insert(dlink *newlink)
{
    if (prev)
	prev->next = newlink;

    newlink->next = this;
    newlink->prev = prev;
    prev = newlink;
}
!EOF!
ls -l 7_6c.c
echo x - 7_6d.c
sed 's/^X//' > 7_6d.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// append a dlink after this one
void dlink::append(dlink *newlink)
{
    if (next)
	next->prev = newlink;

    newlink->next = next;
    newlink->prev = this;
    next = newlink;
}
!EOF!
ls -l 7_6d.c
echo x - 7_6e.c
sed 's/^X//' > 7_6e.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// remove this link from the list
void dlink::remove()
{
    if (prev)
	prev->next = next;

    if (next)
	next->prev = prev;

    next = prev = 0;
}
!EOF!
ls -l 7_6e.c
echo x - 7_6f.h
sed 's/^X//' > 7_6f.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// manage a doubly-linked list
class dlist
{
    dlink *last;
    dlink *curr;

public:
    dlist();
    dlist(ent e);
    ~dlist();
    int isempty() { return last != 0; }
    void clear();

    // set current pointer to the ends of the list
    void reset() { curr = 0; }

    // move around the list, leaving the links there
    int next(ent &e);
    int prev(ent &e);

    // move around the list, removing the links
    int getnext(ent &e);
    int getprev(ent &e);

    // manipulate around the beginning
    // and end of the list
    void insert(ent e);
    void append(ent e);

    // manipulate around the current entry
    void inserthere(ent e);
    void appendhere(ent e);
};
!EOF!
ls -l 7_6f.h
echo x - 7_6g1.gc
sed 's/^X//' > 7_6g1.gc << '!EOF!'
X.DS CB
X.GS
                                                  slist::last
                                                      |
                                                      v
    --------    --------    --------             --------
 @->| next |--->| next |--->| next |---> ... --->| next |--@
 |  --------    --------    --------             --------  |
 |  | ent  |    | ent  |    | ent  |             | ent  |  |
 |  --------    --------    --------             --------  |
 |                                                         @
 @---------------------------------------------------------
X.GE
X.DE
!EOF!
ls -l 7_6g1.gc
echo x - 7_6g2.gc
sed 's/^X//' > 7_6g2.gc << '!EOF!'
X.DS CB
X.GS
                                                  dlist::last
                                                      |
                                                      v
      --------    --------    --------             --------
 @--->| next |--->| next |--->| next |---> ... --->| next |----@
 |    --------    --------    --------             --------    |
 | @--| prev |<---| prev |<---| prev |<--- ... <---| prev |<-@ |
 | |  --------    --------    --------             --------  | |
 | |  | ent  |    | ent  |    | ent  |             | ent  |  | |
 | |  --------    --------    --------             --------  | |
 | |                                                         | |
 | @---------------------------------------------------------@ |
 @-------------------------------------------------------------@
X.GE
X.DE
!EOF!
ls -l 7_6g2.gc
echo x - 7_6gI1.gc
sed 's/^X//' > 7_6gI1.gc << '!EOF!'
X.DS CB
X.GS
         X          this
         |           |
	 v           v
      --------    --------
      | next |--->| next |
      --------    --------
      | prev |<---| prev |
      --------    --------
      | ent  |    | ent  |
      --------    --------
X.GE
X.DE
!EOF!
ls -l 7_6gI1.gc
echo x - 7_6gI2.gc
sed 's/^X//' > 7_6gI2.gc << '!EOF!'
X.DS CB
X.GS
         X          new         this
         |           |           |
	 v           v           v
      --------    --------    --------
      | next |--->| next |--->| next |
      --------    --------    --------
      | prev |<---| prev |<---| prev |
      --------    --------    --------
      | ent  |    | ent  |    | ent  |
      --------    --------    --------
X.GE
X.DE
!EOF!
ls -l 7_6gI2.gc
echo x - all.c
sed 's/^X//' > all.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "7_6a.h"
#include "7_6b.h"
#include "7_6f.h"

#include "7_6_app.c"
#include "7_6_apph.c"
#include "7_6_clear.c"
#include "7_6_cons1.c"
#include "7_6_cons2.c"
#include "7_6_getn.c"
#include "7_6_getp.c"
#include "7_6_ins.c"
#include "7_6_insh.c"
#include "7_6_next.c"
#include "7_6_prev.c"
#include "7_6c.c"
#include "7_6d.c"
#include "7_6e.c"
#include "7_6_dest.c"
!EOF!
ls -l all.c
echo x - makefile
sed 's/^X//' > makefile << '!EOF!'
CC= CC -I. -I../../CC

all: tst

tst: tst.o all.o
	$(CC) -o tst tst.o all.o

tst.o: tst.c 7_6a.h 7_6b.h 7_6f.h
	$(CC) -c tst.c

all.o: all.c 7_6a.h 7_6b.h 7_6f.h 7_6_app.c 7_6_apph.c 7_6_clear.c 7_6_cons1.c 7_6_cons2.c 7_6_getn.c 7_6_getp.c 7_6_ins.c 7_6_insh.c 7_6_next.c 7_6_prev.c 7_6_dest.c 7_6c.c 7_6d.c 7_6e.c
	$(CC) -c all.c

CMP= tst.cmp
OUT= tst.out

tst.out: tst ; tst > tst.out

test: all $(CMP) $(OUT)
	cmp tst.out tst.cmp
	@echo test done
!EOF!
ls -l makefile
echo x - tst.c
sed 's/^X//' > tst.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "7_6a.h"
#include "7_6b.h"
#include "7_6f.h"

#include <stream.h>

main()
{
    dlist xdlist("hello");
    xdlist.append("there");
    xdlist.append("how");
    xdlist.append("are");
    xdlist.append("you");
    xdlist.append("today");
    void *x;
    cout << "forwards\n";
    while (xdlist.next(x))
	cout << "'" << (char*)x << "'\n";
    cout << "\nbackwards\n";
    while (xdlist.prev(x))
	cout << "'" << (char*)x << "'\n";
    xdlist.next(x);
    xdlist.next(x);
    xdlist.inserthere("Beep");
    xdlist.appendhere("Boop");
    xdlist.reset();
    cout << "\nforwards, removing\n";
    while (xdlist.getnext(x))
	cout << "'" << (char*)x << "'\n";
    cout << "\nbackwards\n";
    while (xdlist.getprev(x))
	cout << "'" << (char*)x << "'\n";
    return 0;
}
!EOF!
ls -l tst.c
echo x - tst.cmp
sed 's/^X//' > tst.cmp << '!EOF!'
forwards
'hello'
'there'
'how'
'are'
'you'
'today'

backwards
'today'
'you'
'are'
'how'
'there'
'hello'

forwards, removing
'hello'
'Beep'
'there'
'Boop'
'how'
'are'
'you'
'today'

backwards
!EOF!
ls -l tst.cmp
# The following exit is to ensure that extra garbage 
# after the end of the shar file will be ignored.
exit 0