#!/bin/sh
# This is a shar archive.
# The rest of this file is a shell script which will extract:
#
# 5_6A.h 5_6B.h 5_6a.c 5_6a.cmp 5_6b.c 5_6b.cmp 5_6test.c char_queue.h makefile
#
# 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 23:04:03 EDT 1990
#
echo x - 5_6A.h
sed 's/^X//' > 5_6A.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Exercise 5.6, part 1
// Implement a character queue using a linked list.
// <char_queue.h>
#ifndef CHAR_QUEUE_H
# define CHAR_QUEUE_H

class char_queue
{
    struct cQtable
    {
        char c;
	struct cQtable *next;
    } *rear, *front;

public:
    char_queue(int nummembers);
    ~char_queue();

    void enqueue(char s);
    char dequeue();
    int emptyQ() { return (front == 0); }
    void clearQ();
};
#endif /* CHAR_QUEUE_H */
!EOF!
ls -l 5_6A.h
echo x - 5_6B.h
sed 's/^X//' > 5_6B.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Exercise 5.6, part 2
// Implement a character queue using a vector.
// <char_queue.h>
#ifndef CHAR_QUEUE_H
# define CHAR_QUEUE_H

class char_queue
{
    char *base, *front, *rear, *end;

public:
    char_queue(int nummembers);
    ~char_queue();

    void enqueue(char s);
    char dequeue();
    int emptyQ() { return (rear == front); }
    void clearQ();
};
#endif /* CHAR_QUEUE_H */
!EOF!
ls -l 5_6B.h
echo x - 5_6a.c
sed 's/^X//' > 5_6a.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// implement a character queue using
// a linked list
#include <char_queue.h>
#include <error.h>

char_queue:: char_queue(int)
{
    rear = front = 0;
}

char_queue:: ~char_queue()
{
    this->clearQ();
}

void char_queue:: enqueue(char c)
{
    if (rear)
	{
	rear->next = new cQtable;
	rear = rear->next;
	}

    else
	front = rear = new cQtable;

    rear->next = 0;
    rear->c = c;
}

char char_queue:: dequeue()
{
    if (emptyQ())
	error("underflow of character queue");

    char c = front->c;
    if (front == rear)
	{
	delete front;
	rear = front = 0;
	}

    else
	{
	cQtable *old = front;
	front = front->next;
	delete old;
	}

    return c;
}

void char_queue:: clearQ()
{
    while (front)
	{
	cQtable *old = front;
	front = front->next;
	delete old;
	}

    rear = 0;
}
!EOF!
ls -l 5_6a.c
echo x - 5_6a.cmp
sed 's/^X//' > 5_6a.cmp << '!EOF!'
adding t
adding h
adding i
adding s
adding  
adding i
adding s
adding  
adding a
adding  
adding t
adding e
adding s
adding t
got t
got h
got i
got s
got  
got i
got s
got  
got a
got  
got t
got e
got s
got t
!EOF!
ls -l 5_6a.cmp
echo x - 5_6b.c
sed 's/^X//' > 5_6b.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// implement a character queue using
// an array
#include <char_queue.h>
#include <error.h>

char_queue:: char_queue(int nummembers)
{
    base = new char[nummembers];
    end = &base[nummembers];
    front = rear = base;
}

char_queue:: ~char_queue()
{
    delete base;
}

void char_queue:: enqueue(char c)
{
    *rear++ = c;
    if (rear == end)
        rear = base;
    if (rear == front)
        error("overflow of character queue");
}

char char_queue:: dequeue()
{
    if (emptyQ())
        error("underflow of character queue");
    char ch = *front++;
    if (front == end)
        front = base;
    return ch;
}

void char_queue:: clearQ()
{
    front = rear = base;
}
!EOF!
ls -l 5_6b.c
echo x - 5_6b.cmp
sed 's/^X//' > 5_6b.cmp << '!EOF!'
adding t
adding h
adding i
adding s
adding  
adding i
adding s
adding  
adding a
adding  
adding t
adding e
adding s
adding t
got t
got h
got i
got s
got  
got i
got s
got  
got a
got  
got t
got e
got s
got t
!EOF!
ls -l 5_6b.cmp
echo x - 5_6test.c
sed 's/^X//' > 5_6test.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "char_queue.h"
#include <stream.h>

char array[] = "this is a test";

main()
{
    char_queue c(100);
    
    for (char *a = array; *a; a++)
        {
	char x = *a;
	cout << "adding " << chr(x) << "\n";
        c.enqueue(x);
	}

    while (!c.emptyQ())
        {
	char x = c.dequeue();
	cout << "got " << chr(x) << "\n";
	}
    return 0;
}
!EOF!
ls -l 5_6test.c
echo x - char_queue.h
sed 's/^X//' > char_queue.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#ifdef A
#include "5_6A.h"
#else
#include "5_6B.h"
#endif
!EOF!
ls -l char_queue.h
echo x - makefile
sed 's/^X//' > makefile << '!EOF!'
CC= CC -I. -I../../CC
ERROR=  ../../error.o
CFLAGS= -g -I.

all: 5_6a 5_6b

5_6a: 5_6a.o 5_6test.c
	$(CC) $(CFLAGS) -DA 5_6a.o 5_6test.c -o 5_6a $(ERROR)

5_6b: 5_6b.o 5_6test.c
	$(CC) $(CFLAGS) -DB 5_6b.o 5_6test.c -o 5_6b $(ERROR)

5_6a.o: 5_6a.c 5_6A.h char_queue.h
	$(CC) $(CFLAGS) -DA -c 5_6a.c

5_6b.o: 5_6b.c 5_6B.h char_queue.h
	$(CC) $(CFLAGS) -DB -c 5_6b.c

CMP= 5_6a.cmp 5_6b.cmp
OUT= 5_6a.out 5_6b.out

5_6a.out: 5_6a ;	5_6a > 5_6a.out
5_6b.out: 5_6b ;	5_6b > 5_6b.out

test: all $(OUT) $(CMP)
	cmp 5_6a.out 5_6a.cmp
	cmp 5_6b.out 5_6b.cmp
	echo tests done
!EOF!
ls -l makefile
# The following exit is to ensure that extra garbage 
# after the end of the shar file will be ignored.
exit 0