Sunshine Books Advanced Programming Techniques on the Commodore 64 a

agvanced

programming

techniques

on

powerful

david

the

commodore

ideas

lawrence

and

applications

64

aovanced

programming

techniques

on

powerful

david

the

commodore

ideas

lawrence

and

applications

64

First

published

Sunshine

12-13

Little

London

WC2R

Books

Newport

1983

(an

3LD

by: imprint

Street,

of

Scot

Press

Ltd.)

Reprinted

1984

ISBN 0 946408

All

rights

in a retrieval

electronic, the

prior

23

8

reserved.

system,

mechanical,

written

permission

Lawrence

No

part

of

.or

transmitted

photocopying,

of

the

this

publication

in

recording

Publishers.

any

may

form

and/or

be

reproduced,

or

by

otherwise,

any

stored

means,

without

Cover

Design

Illustration

Typeset

il

and

by

Graphic

by

Stuart

printed

Design

Hughes.

in

England

Ltd.

by

The

Leagrave

Press

Ltd.

CONTENTS

Page

Notes

Introduction

1

2

3

4

5

6

7

8

9

on

Program

Modular

Debugging

Strings

Inputting

Error

Storing

Logical

A

Data

Trapping

and

Conditions

Jungle

Structures:

Listings

Programming

Information

Retrieving

of

Sorts

I

1X

1

3

17

2/

41

53

65

79

93

111

10

Data

11

Inserting

12

Odds

13

Formatting

Postword

Structures:

Data

and

Ends

II

127

141

149

159

171

Contents

in

detail

CHAPTER

Modular A

guide planning hints

and

CHAPTER

Debugging Information — single

—

interpreting

CHAPTER

Strings Concatenation

into a string — moving

—

regular

variable

CHAPTER

Inputting Entering

of

several GET — GET —

GET with

GET — simple

1

Programming

to

writing

the

program — writing

tips.

programs

2

error

messages.

3

or

string

structures — multiple

length

strings — garbage

4

Information

information:

items

using

and

creating a waiting

and

timed

responses — GET

screen

that

work — defining

the

modules — entering

line

error

messages — non-obvious

addition — string

items within a string — searching

collection.

INPUT — simple

the

same

screen

editing

using

subtraction — inserting

element

entries

line — INPUT

state — moving a cursor

and

inverse

INPUT.

string

with

boxes — screen

your

program

the

program

error

messages

items

within

arrays — data

INPUT — INPUT

to

screen

strings

boxes

with

editing

GET

— —

in

—

CHAPTER

Error

Trapping

Avoiding

common

5

errors — error

sense

error-trapping — DIY

trapping — setting

error

messages.

limits — garbled

entries

—

Advanced

Programming

Techniques

CHAPTER

Storing

Saving to a file — loading disk.

and

programs — saving

6

Retrieving

from

CHAPTER7

Logical

The

IF — IF... AND conditions — setting

the — with

odd

CHAPTER

A The

the

Sort.

Conditions

humble

value

multiplying

numbers — POKE

or

IF — protecting

THEN...ELSE

and

OR

of a condition — using

and

even?

8

Jungle

of

whys

Bubble

Sorts

and

wherefores

Sort — the

—

combining

dividing — avoiding

and

loading

tape

—-

against

—

IF

limits — IF

with

AND

of

sorting — the

Delayed

data — saving

Save

and

illegal

with

>,<

AND

and

with

NOT — using

conditions

isolation

and

OR — storing

Replacement

to

tape — printing

Load

routines — variations

values — errors

and = —

OR

Bubble

IF

with

—

unpacking

logical

as

values — plus

by

IF — AND

with

Sort — programming

Sort — the

Shell-Metzner

for

arising

the

conditions

AND/OR

from

operators

complex

—

or

minus?

and

OR

—

CHAPTER

Data

Structures:

Simple numbers in strings

CHAPTER

Data Linked

problem.

CHAPTER

Inserting

Normal

searching

data

strings — stacks — string

using

Structures:

lists — pointer

9

I

structures — data

in

integer

numeric

Data

search and

with

arrays — storing

10

IT

|

11

shift — binary

pointer

array

arrays.

structures

directly

data

structures — packed

pointers.

strings — deleting

searching — pure

for

numbers — single

in

free

with

pointers — the

byte

memory — numbers

strings — packed

black

hole

searching — binary

CHAPTER

Odds

and

User

defined

—

timing

12

Ends

functions — terminating

with

TI

and

TI$ — rounding

FOR

with

loops — DATA

INT.

statements

CHAPTER

Formatting

Cursor

simulating

controls — use

PRINT

13

of

cursor

USING — justifying — easy

control

characters — TAB

logos

and

designs.

—

SPC

—

Notes

For

the

follow

have

on

program

sake

been

of

clarity,

set

listings

control

out

as

follows:

characters

in

the

program

lines

whicly

CURSOR

UF

CURSOR

CLEAR

HOME

SCREEN

CURSOR

REVERSE

Colours

control

are

represented

character

[YELLOW

J

Where a number instance:

DOWN

LEFT

RIGHT

ON

OFF

for

yellow

of

by

the

1s:

control

colour

name

characters

in

are

required

square

CCU

CCD

I

CCL

CCR

I

CCLRI

CHOME

CRV&S

CTRVS

brackets.

the

format

J

ONI

OFF

Thus

is,

J

the

for

rigsg*xCbDJ

Within and

should

program

be

replaced

listings,

single

when

quotes

listings

are

used

entered.

in

place

of

double

quotes

Introduction

This

book

is

intended

is

not a collection

available

to

write a two

The

64,

of

The the only problem

There

most

something

then

and

How will

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book

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Working

era

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simply

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What

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alongside

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they

can

The

complexity chapters single objectives and

that

line

like

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BASIC.

line

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is

dedicated,

who

want

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normally

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made

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64,

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Centigrade.

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Advanced

Programming

Techniques

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4

Chapter 1 Modular

Programming

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15

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Advanced

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25

Advanced

Programming

Techniques

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26

CHAPTER

Strings

3

Strings

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27

Advanced

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31

Advanced

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33

Advanced

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37

Advanced

Programming

Techniques

Garbage

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39

CHAPTER

4

Inputting

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41

Advanced

Programming

Techniques

immediately,

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63

CHAPTER

6

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65

Advanced

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Saving

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Advanced

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78

CHAPTER

7

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