DOCSLIB.ORG

4.3 Stacks and Queues

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
4.3 Stacks and Queues 4.3 Stacks and Queues 1 Data Structures and Data Types Collections Data types Fundamental data types. • Set of values. • Set of operations (add, remove, test if empty) on generic data. • Set of operations on those values. • Intent is clear when we insert. • Some are built in to Java: int, double, char, String, . • Which item do we remove? Most are not: Complex, Picture, Charge, Stack, Queue, Graph, . • LIFO = "last in first out" Stack. (this lecture) this lecture Data structures. • Remove the item most recently added. • Represent data. • Ex: cafeteria trays, Web surfing. Represent relationships among data. • FIFO = "first in first out" • Some are built in to Java: arrays, . Queue. (see text) • Most are not: linked list, circular list, tree, sparse array, graph, . • Remove the item least recently added. • Ex: Registrar's line. this lecture TSP next lecture (assignment 8) Symbol Table. (next lecture) Design challenge for every data type: What data structure to use? • Remove item with a given key. • Requirement 1: Space usage. • Ex: Phone book • Requirement 2: Time usage for data-type methods 3 4 FIFO Queue API FIFO Queues public class QueueOfStrings QueueOfStrings() create an empty queue int length() size of the queue void put(String item) put a string onto the queue String get() get a string from the queue it it was put was get was get the the the the length best best best best 3 of of of 5 6 Queue Client Code Example: Read from input stream into an array from previous lecture public class WhiteFilter { public static void main(String[] args) Pushdown Stacks { In in = new In(args[0]); String[] words; // Fill words[] with strings from In (stay tuned). while (!StdIn.isEmpty()) { String key = StdIn.readString(); if (search(key, words) != -1) StdOut.println(key); QueueOfStrings q = new QueueOfStrings(); } while (!in.isEmpty()) } q.put(in.readString()); } int N = q.length(); words = new String[N]; for (int i = 0; i < N; i++) words[i] = q.get(); Solves basic problem • Can’t store strings in array until it is created. • Can’t create array without knowing how many strings in input stream. • Can’t know how many strings in input stream without reading them all. • Solution: keep them in a Queue See text for implementation/applications (after learning about Stacks). 7 8 Stack API Stack Client Example 1: Reverse public class Reverse { public static void main(String[] args) { StackOfStrings stack = new StackOfStrings(); while (!StdIn.isEmpty()) stack.push(StdIn.readString()); while (!stack.isEmpty()) StdOut.print(stack.pop()); *: we will consider more than one implementation StdOut.println(); } } % more tiny.txt it was the best of times times % java Reverse tiny.txt times of of of times of best the was it of best push best pop best pop best the the the the best stack contents when StdIn is empty was was was was the it it it it was it 9 10 Stack Client Example 2: Test Client Stack Client Example 3: Balanced Parentheses public static void main(String[] args) { StackOfStrings stack = new StackOfStrings(); while (!StdIn.isEmpty()) { String item = StdIn.readString(); ( ( ( a + b ) * d ) + ( e * f ) ) if (item.compareTo("-") != 0) stack.push(item); ( ) else ( ) ( ) System.out.print(stack.pop()); ( ) } push pop System.out.println(); push pop push pop } % more test.txt push pop to be or not to - be - - that - - - is % java StackOfStrings < test.txt to be not that or be to not stack contents just before first pop() operation or be to 11 12 Stack Client Example 3: Balanced Parentheses Stack: Array Implementation public class Balanced { Array implementation of a stack. public static void main(String[] args) • Use array a[] to store N items on stack. PROBLEM: How big to make array? (Stay tuned.) { push StackOfStrings stack = new StackOfStrings(); • push() add new item at a[N]. while (!StdIn.isEmpty()) pop() remove item from a[N-1]. { • pop String item = StdIn.readString(); if (item.compareTo("(") == 0) Strawman solution: Make client provide capacity. stack.push(item); public class ArrayStackOfStrings NOTE: This ‘solution’ violates the API! if (item.compareTo(")") == 0) { { private String[] a; if (stack.isEmpty()) private int N = 0; { StdOut.println(“Not balanced”); return; } stack.pop(); public ArrayStackOfStrings(int max) } { a = new String[max]; } } not stack contents after if (!stack.isEmpty()) StdOut.println(“Not balanced”); public boolean isEmpty() 4th push() operation else StdOut.println(“Balanced”); or } { return (N == 0); } } be % java Balanced public void push(String item) ( ( ( a + b ) * d ) + ( e * f ) ) { a[N++] = item; } to N Balanced public String pop() % java Balanced { return a[--N]; } to be or not ( ( a + b ) * d ) + ( e * f ) ) Not balanced } a[0] a[1] a[2] a[3] 13 14 Array Stack: Trace TEQ on Stacks Q. Can we always insert pop commands (-) to make strings come out sorted? Ex 1: 6 5 4 3 2 1 - - - - - push Ex 2: 1 - 2 - 3 - 4 - 5 - 6 - Ex 3: 4 1 - 3 2 - - - 6 5 - - pop 15 16 Array Stack: Performance Example: potential stack client Possible implementation of Java memory management system (sketch) Running time. Push and pop take constant time. ✓ Maintain N stacks stack i: blocks of contiguous 2i byte chunks of memory Memory. Proportional to client-supplied capacity, not number of items. ✗ • • new: pop from stack t, where 2t is smallest block that will hold new object stack t empty? pop from t+1, split in half, push 2 blocks on stack t Problem. • garbage collector: periodically finds unused memory blocks How? See COS 226. Original API does not call for capacity (never good to change API) • • and pushes onto appropriate stack. • Client might have multiple stacks • Client might not know what capacity to use (depends on its client) Properties • many stacks • stack size unpredictable . 2 4 8 16 Stack implementation without capacity restriction (as in API) is a requirement Challenge. Stack implementation where space use is not fixed ahead of time. 17 18 Sequential vs. Linked Data Structures Linked Lists Sequential data structure. Put object one next to another. • TOY: consecutive memory cells. • Java: array of objects. Linked data structure. Include in each object a link to the another one. • TOY: link is memory address of next object. • Java: link is reference to next object. addr value addr value C0 "Alice" C0 "Carol" C1 "Bob" C1 null th Key distinctions. get i element C2 "Carol" C2 - Array: arbitrary access, fixed size. C3 - C3 - • C4 - C4 "Alice" Linked list: sequential access, variable size. • C5 - C5 CA C6 - C6 - get next element C7 - C7 - C8 - C8 - C9 - C9 - Linked structures. CA - CA "Bob" CB - CB C0 • Not intuitive, overlooked by naive programmers linked list • Flexible, widely used method for organizing data array 19 20 Singly-linked data structures Linked Lists From the point of view of a particular object, all of these structures Linked list. look the same: • Simplest linked structure. A recursive data structure. Sequential list (this lecture) Rho • • An item plus a pointer to another linked list (or empty list). • Unwind recursion: linked list is a sequence of items. Tree Circular list (TSP) Node data type. public class Node { A reference to a String. • private String item; • A reference to another Node. private Node next; } Confusing point: General case Purpose of data structure is to represent data in a data type but, we also use data types to implement data structures Example: The data type Node acts behind the scenes to implement the linked list data structure. It is not visible to the client. first Alice Bob Carol item next Multiply linked structures: many more possibilities! special pointer value null terminates list 21 22 Building a Linked List Traversing a List Iteration. Idiom for traversing a null-terminated linked list. addr Value Node third = new Node(); third.item = "Carol"; C0 "Carol" third.next = null; C1 null Node x = first; Node second = new Node(); C2 - while (x != null) second.item = "Bob"; C3 - { second.next = third; StdOut.println(x.item); first C4 C4 "Alice" x = x.next; Node first = new Node(); } first.item = "Alice"; second CA C5 CA first.next = second; third C0 C6 - shorthand version C7 - for (Node x = first; x != null; x = x.next) C8 - StdOut.println(x.item); C9 - CA "Bob" CB C0 first second third StdOut CC - first CD - Alice Bob Carol Alice Bob Carol CE - item next item next null CF - main memory 23 24 Stack Push: Linked List Implementation Stack Pop: Linked List Implementation first "of" best the was it first of best the was it item = first.item; first second best the was it second = first; first of best the was it first = first.next; first second garbage-collected best the was it first = new Node(); first first second best the was it return item; of best the was it first.item = item; first.next = second; 25 26 Stack: Linked List Implementation Linked List Stack: Trace public class LinkedStackOfStrings { private Node first = null; push private class Node not stack contents after { 4th push() operation private String item; or in test client private Node next; } be public boolean isEmpty() to { return first == null; } pop public void push(String item) { first Node second = first; first = new Node(); not first.item = item; first.next = second; } or public String pop() be { String item = first.item; to first = first.next; Note difference between first and second: return item; first: an instance variable that retains state } second: a local variable that goes out of scope } 27 28 Linked-List Stack: Performance Stack Data Structures: Tradeoffs Two data structures to implement the Stack data type. Running time. Push and pop take constant time. ✓ Memory. Always proportional to number of items in stack. ✓ Array. • Every push/pop operation take constant time. • But does not implement API… (must fix max capacity ahead of time).
Load more

Recommended publications
  • 15-122: Principles of Imperative Computation, Fall 2014 Lab 11: Strings in C
    15-122: Principles of Imperative Computation, Fall 2014 Lab 11: Strings in C Tom Cortina(tcortina@cs) and Rob Simmons(rjsimmon@cs) Monday, November 10, 2014 For this lab, you will show your TA your answers once you complete your activities. Autolab is not used for this lab. SETUP: Make a directory lab11 in your private 15122 directory and copy the required lab files to your lab11 directory: cd private/15122 mkdir lab11 cp /afs/andrew.cmu.edu/usr9/tcortina/public/15122-f14/*.c lab11 1 Storing and using strings using C Load the file lab11ex1.c into a text editor. Read through the file and write down what you think the output will be before you run the program. (The ASCII value of 'a' is 97.) Then compile and run the program. Be sure to use all of the required flags for the C compiler. Answer the following questions on paper: Exercise 1. When word is initially printed out character by character, why does only one character get printed? Exercise 2. Change the program so word[3] = 'd'. Recompile and rerun. Explain the change in the output. Run valgrind on your program. How do the messages from valgrind correspond to the change we made? Exercise 3. Change word[3] back. Uncomment the code that treats the four character array word as a 32-bit integer. Compile and run again. Based on the answer, how are bytes of an integer stored on the computer where you are running your code? 2 Arrays of strings Load the file lab11ex2.c into a text editor.
    [Show full text]
  • Unibasic 9.3 Reference Guide
    Unibasic - Dynamic Concepts Wiki 6/19/17, 1244 PM Unibasic From Dynamic Concepts Wiki Contents 1 UniBasic 2 About this Guide 2.1 Conventions 3 Installation & Configuration 3.1 Configuring Unix for UniBasic 3.1.1 Number of Processes 3.1.2 Number of Open Files 3.1.3 Number of Open i-nodes 3.1.4 Number of Locks 3.1.5 Message Queues 3.2 Unix Accounting & Protection System 3.3 Creating a Unix Account for UniBasic 3.4 UniBasic Security & Licensing 3.4.1 Software Licensing 3.4.2 Hardware Licensing 3.5 Loading the Installation File 3.5.1 Loading the UniBasic Installation File 3.5.2 Loading the UniBasic Development File 3.6 ubinstall - Installing UniBasic Packages 3.6.1 Errors During Installation 3.7 Configuring a UniBasic Environment 3.7.1 Directories and Paths 3.7.2 Filenames and Pathnames 3.7.3 Organizing Logical Units and Packnames 3.7.4 Environment Variables 3.7.5 Setting up .profile for Multiple Users 3.8 Command Line Interpreter 3.9 Launching UniBasic From Unix 3.10 Terminating a UniBasic Process 3.11 Licensing a New Installation 3.12 Changing the SSN Activation Key 3.13 Launching UniBasic Ports at Startup 3.14 Configuring Printer Drivers 3.15 Configuring Serial Printers 3.16 Configuring Terminal Drivers 3.17 Creating a Customized Installation Media 4 Introduction To UniBasic 4.1 Data 4.1.1 Numeric Data 4.1.1.1 Numeric Precision 4.1.1.2 Special Notes on %3 and %6 Numerics https://engineering.dynamic.com/mediawiki/index.php?title=Unibasic&printable=yes Page 1 of 397 Unibasic - Dynamic Concepts Wiki 6/19/17, 1244 PM 4.1.1.3 Integers Stored in Floating-Point
    [Show full text]
  • IBM Education Assistance for Z/OS V2R1
    IBM Education Assistance for z/OS V2R1 Item: ASCII Unicode Option Element/Component: UNIX Shells and Utilities (S&U) Material is current as of June 2013 © 2013 IBM Corporation Filename: zOS V2R1 USS S&U ASCII Unicode Option Agenda ■ Trademarks ■ Presentation Objectives ■ Overview ■ Usage & Invocation ■ Migration & Coexistence Considerations ■ Presentation Summary ■ Appendix Page 2 of 19 © 2013 IBM Corporation Filename: zOS V2R1 USS S&U ASCII Unicode Option IBM Presentation Template Full Version Trademarks ■ See url http://www.ibm.com/legal/copytrade.shtml for a list of trademarks. Page 3 of 19 © 2013 IBM Corporation Filename: zOS V2R1 USS S&U ASCII Unicode Option IBM Presentation Template Full Presentation Objectives ■ Introduce the features and benefits of the new z/OS UNIX Shells and Utilities (S&U) support for working with ASCII/Unicode files. Page 4 of 19 © 2013 IBM Corporation Filename: zOS V2R1 USS S&U ASCII Unicode Option IBM Presentation Template Full Version Overview ■ Problem Statement –As a z/OS UNIX Shells & Utilities user, I want the ability to control the text conversion of input files used by the S&U commands. –As a z/OS UNIX Shells & Utilities user, I want the ability to run tagged shell scripts (tcsh scripts and SBCS sh scripts) under different SBCS locales. ■ Solution –Add –W filecodeset=codeset,pgmcodeset=codeset option on several S&U commands to enable text conversion – consistent with support added to vi and ex in V1R13. –Add –B option on several S&U commands to disable automatic text conversion – consistent with other commands that already have this override support. –Add new _TEXT_CONV environment variable to enable or disable text conversion.
    [Show full text]
  • Bidirectional Programming Languages
    University of Pennsylvania ScholarlyCommons Publicly Accessible Penn Dissertations Winter 2009 Bidirectional Programming Languages John Nathan Foster University of Pennsylvania, [email protected] Follow this and additional works at: https://repository.upenn.edu/edissertations Part of the Databases and Information Systems Commons, and the Programming Languages and Compilers Commons Recommended Citation Foster, John Nathan, "Bidirectional Programming Languages" (2009). Publicly Accessible Penn Dissertations. 56. https://repository.upenn.edu/edissertations/56 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/edissertations/56 For more information, please contact [email protected]. Bidirectional Programming Languages Abstract The need to edit source data through a view arises in a host of applications across many different areas of computing. Unfortunately, few existing systems provide support for updatable views. In practice, when they are needed, updatable views are usually implemented using two separate programs: one that computes the view from the source and another that handles updates. This rudimentary design is tedious for programmers, difficult to reason about, and a nightmare to maintain. This dissertation presents bidirectional programming languages, which provide an elegant and effective mechanism for describing updatable views. Unlike programs written in an ordinary language, which only work in one direction, programs in a bidirectional language can be run both forwards and backwards: from left to right, they describe functions that map sources to views, and from right to left, they describe functions that map updated views back to updated sources. Besides eliminating redundancy, these languages can be designed to ensure correctness, guaranteeing by construction that the two functions work well together. Starting from the foundations, we define a general semantic space of well-behaved bidirectional transformations called lenses.
    [Show full text]
  • Reference Manual for the Icon Programming Language Version 5 (( Implementation for Limx)*
    Reference Manual for the Icon Programming Language Version 5 (( Implementation for liMX)* Can A. Contain. Ralph £ Grixwoltl, and Stephen B. Watnplcr "RSI-4a December 1981, Corrected July 1982 Department of Computer Science The University of Arizona Tucson, Arizona 85721 This work was supported by the National Science Foundation under Grant MCS79-03890. Copyright © 1981 by Ralph E. Griswold All rights reserved. No part of this work may be reproduced, transmitted, or stored in any form or by any means without the prior written consent of the copyright owner. CONTENTS Chapter i Introduction 1.1 Background I 1.2 Scope ol the Manual 2 1.3 An Overview of Icon 2 1.4 Syntax Notation 2 1.5 Organization ol the Manual 3 Chapter 2 Basic Concepts and Operations 2.1 Types 4 2.2 Expressions 4 2.2.1 Variables and Assignment 4 2.2.2 Keywords 5 2.2.3 Functions 5 2.2.4 Operators 6 2.3 Evaluation of Expressions 6 2.3.1 Results 6 2.3.2 Success and Failure 7 2.4 Basic Control Structures 7 2.5 Compound Expressions 9 2.6 Loop Control 9 2.7 Procedures 9 Chapter 3 Generators and Expression Evaluation 3.1 Generators 11 3.2 Goal-Directed Evaluation 12 }.?> Evaluation of Expres.sions 13 3.4 I he Extent ol Backtracking 14 3.5 I he Reversal ol Effects 14 Chapter 4 Numbers and Arithmetic Operations 4.1 Integers 15 4.1.1 literal Integers 15 4.1.2 Integer Arithmetic 15 4.1.3 Integer Comparison 16 4.2 Real Numbers 17 4.2.1 literal Real Numbers 17 4.2.2 Real Arithmetic 17 4.2.3 Comparison of Real Numbers IS 4.3 Mixed-Mode Arithmetic IX 4.4 Arithmetic Type Conversion 19
    [Show full text]
  • Software II: Principles of Programming Languages
    Software II: Principles of Programming Languages Lecture 6 – Data Types Some Basic Definitions • A data type defines a collection of data objects and a set of predefined operations on those objects • A descriptor is the collection of the attributes of a variable • An object represents an instance of a user- defined (abstract data) type • One design issue for all data types: What operations are defined and how are they specified? Primitive Data Types • Almost all programming languages provide a set of primitive data types • Primitive data types: Those not defined in terms of other data types • Some primitive data types are merely reflections of the hardware • Others require only a little non-hardware support for their implementation The Integer Data Type • Almost always an exact reflection of the hardware so the mapping is trivial • There may be as many as eight different integer types in a language • Java’s signed integer sizes: byte , short , int , long The Floating Point Data Type • Model real numbers, but only as approximations • Languages for scientific use support at least two floating-point types (e.g., float and double ; sometimes more • Usually exactly like the hardware, but not always • IEEE Floating-Point Standard 754 Complex Data Type • Some languages support a complex type, e.g., C99, Fortran, and Python • Each value consists of two floats, the real part and the imaginary part • Literal form real component – (in Fortran: (7, 3) imaginary – (in Python): (7 + 3j) component The Decimal Data Type • For business applications (money)
    [Show full text]
  • Standard TECO (Text Editor and Corrector)
    Standard TECO TextEditor and Corrector for the VAX, PDP-11, PDP-10, and PDP-8 May 1990 This manual was updated for the online version only in May 1990. User’s Guide and Language Reference Manual TECO-32 Version 40 TECO-11 Version 40 TECO-10 Version 3 TECO-8 Version 7 This manual describes the TECO Text Editor and COrrector. It includes a description for the novice user and an in-depth discussion of all available commands for more advanced users. General permission to copy or modify, but not for profit, is hereby granted, provided that the copyright notice is included and reference made to the fact that reproduction privileges were granted by the TECO SIG. © Digital Equipment Corporation 1979, 1985, 1990 TECO SIG. All Rights Reserved. This document was prepared using DECdocument, Version 3.3-1b. Contents Preface ............................................................ xvii Introduction ........................................................ xix Preface to the May 1985 edition ...................................... xxiii Preface to the May 1990 edition ...................................... xxv 1 Basics of TECO 1.1 Using TECO ................................................ 1–1 1.2 Data Structure Fundamentals . ................................ 1–2 1.3 File Selection Commands ...................................... 1–3 1.3.1 Simplified File Selection .................................... 1–3 1.3.2 Input File Specification (ER command) . ....................... 1–4 1.3.3 Output File Specification (EW command) ...................... 1–4 1.3.4 Closing Files (EX command) ................................ 1–5 1.4 Input and Output Commands . ................................ 1–5 1.5 Pointer Positioning Commands . ................................ 1–5 1.6 Type-Out Commands . ........................................ 1–6 1.6.1 Immediate Inspection Commands [not in TECO-10] .............. 1–7 1.7 Text Modification Commands . ................................ 1–7 1.8 Search Commands .
    [Show full text]
  • Rc the Plan 9 Shell
    Rc ߞ The Plan 9 Shell Tom Duff [email protected]−labs.com ABSTRACT Rc is a command interpreter for Plan 9 that provides similar facilities to UNIXߣs Bourne shell, with some small additions and less idiosyncratic syntax. This paper uses numerous examples to describe rcߣs features, and contrasts rc with the Bourne shell, a model that many readers will be familiar with. 1. Introduction Rc is similar in spirit but different in detail from UNIXߣs Bourne shell. This paper describes rcߣs principal features with many small examples and a few larger ones. It assumes familiarity with the Bourne shell. 2. Simple commands For the simplest uses rc has syntax familiar to Bourne-shell users. All of the fol­ lowing behave as expected: date cat /lib/news/build who >user.names who >>user.names wc <file echo [a−f]*.c who | wc who; date vc *.c & mk && v.out /*/bin/fb/* rm −r junk || echo rm failed! 3. Quotation An argument that contains a space or one of rcߣs other syntax characters must be enclosed in apostrophes (’): rm ’odd file name’ An apostrophe in a quoted argument must be doubled: echo ’How’’s your father?’ 4. Patterns An unquoted argument that contains any of the characters *?[is a pattern to be matched against file names. A * character matches any sequence of characters, ? matches any single character, and [class] matches any character in the class, unless the first character of class is ~, in which case the class is complemented. The class may ­ 2 ­ also contain pairs of characters separated by −, standing for all characters lexically between the two.
    [Show full text]
  • IBM ILOG CPLEX Optimization Studio OPL Language Reference Manual
    IBM IBM ILOG CPLEX Optimization Studio OPL Language Reference Manual Version 12 Release 7 Copyright notice Describes general use restrictions and trademarks related to this document and the software described in this document. © Copyright IBM Corp. 1987, 2017 US Government Users Restricted Rights - Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Trademarks IBM, the IBM logo, and ibm.com are trademarks or registered trademarks of International Business Machines Corp., registered in many jurisdictions worldwide. Other product and service names might be trademarks of IBM or other companies. A current list of IBM trademarks is available on the Web at "Copyright and trademark information" at www.ibm.com/legal/copytrade.shtml. Adobe, the Adobe logo, PostScript, and the PostScript logo are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States, and/or other countries. Linux is a registered trademark of Linus Torvalds in the United States, other countries, or both. UNIX is a registered trademark of The Open Group in the United States and other countries. Microsoft, Windows, Windows NT, and the Windows logo are trademarks of Microsoft Corporation in the United States, other countries, or both. Java and all Java-based trademarks and logos are trademarks or registered trademarks of Oracle and/or its affiliates. Other company, product, or service names may be trademarks or service marks of others. © Copyright IBM Corporation 1987, 2017. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Figures ............... v Limitations on constraints ........ 59 Formal parameters ...........
    [Show full text]
  • Just Go for It: the Story of Dance-Mat.Js
    Just go for it: The story of dance-mat.js Ramón Huidobro @hola_soy_milk ramonh.dev/dance-mat-js.pdf CW: Sick late 90’s beats I’m Ramón. Freelance software developer, Mozilla tech speaker. Kids’ coding instructor and football coach. I’m Ramón. Freelance software developer and kids’ coding instructor. @SenorHuidobro Dance Dance Revolution DDR The music. Good gravy, the music. const MPR121 = require('node-picap'); const mpr121 = new MPR121('0x5C'); mpr121.setTouchThreshold(40); mpr121.setReleaseThreshold(20); // Process touches mpr121.on('data', (data) => { try { // SEND DATA TO PC }); } catch(e) { console.log("ERROR: ", e); } }); != https://www.kernel.org/doc/Documentation/usb/gadget_configfs.txt Linux USB gadget configured through configfs https://randomnerdtutorials.com/rasp berry-pi-zero-usb-keyboard-hid/ 1. Enable Raspberry Pi OTG (USB on the go) 2. Add boot script to enable Keyboard HID device on the configfs pi@raspberrypi:~ $ echo "dtoverlay=dwc2" | sudo tee -a /boot/config.txt pi@raspberrypi:~ $ echo "dwc2" | sudo tee -a /etc/modules pi@raspberrypi:~ $ sudo echo "libcomposite" | sudo tee -a /etc/modules 1. Enable Raspberry Pi OTG (USB on the go) 2. Add boot script to enable Keyboard HID device on the configfs #!/bin/bash cd /sys/kernel/config/usb_gadget/ mkdir -p ddrusb cd ddrusb echo 0x1d6b > idVendor # Linux Foundation echo 0x0104 > idProduct # Multifunction Composite Gadget echo 0x0100 > bcdDevice # v1.0.0 echo 0x0200 > bcdUSB # USB2 mkdir -p strings/0x409 echo "fedcba9876543210" > strings/0x409/serialnumber echo "Ramon Huidobro" >
    [Show full text]
  • Numeric and String Variables
    Chapter II-7 II-7Numeric and String Variables Overview.......................................................................................................................................................... 94 Creating Global Variables.............................................................................................................................. 94 Uses For Global Variables.............................................................................................................................. 94 Variable Names ............................................................................................................................................... 94 System Variables ............................................................................................................................................. 95 User Variables ................................................................................................................................................. 95 Special User Variables ............................................................................................................................ 95 Numeric Variables................................................................................................................................... 96 String Variables........................................................................................................................................ 97 Local and Parameter Variables in Procedures ...................................................................................
    [Show full text]
  • Ed: a Context Editor for the Cp/M Disk System User's
    Post Office Box 579, Pacific Grove, California 93950, (408) 373-3403 ED: A CONTEXT EDITOR FOR THE CP/M DISK SYSTEM USER'S MANUAL COPYRIGHT © 1976, 1978 DIGIT AL RESEARCH r Copyright © 1976, 1978 by Digital Research. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or trans­ lated into any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written permission of Digital Research, Post Office Box 579, Pacific Grove, California 93950. Disclaimer Digital Research makes no representations or warranties with respect to the contents hereof and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. Further, Digital Research reserves the right to revise this publication and to make changes from time to time in the content hereof without obligation of Digital Research to notify any person of such revision or changes. Table of Contents 1. ED TUTORIAL • · · · • • · • • 1 l~l Introduction to ED • . 1 1.2 ED Operation .•. 1 1.3 Text Transfer Functions 1 1.4 Memory Buffer Organization. 5 1.5 Memory Buffer Operation..•. 5 1.6 Command Strings 7 1.7 Text Search and Alteration. • • 8 1.8 Source Libraries . • • • . • • 11 1.9 Repetitive Command Execution •• • • 12 2. ED"ERROR CONDITIONS •• . • 13 3. CONTROL CHARACTERS AND COMMANDS . 14 ii ED USER'S MANUAL 1. ED TUTORIAL 1.1. Introduction to ED. ED is the context editor for CP/M, and is used to create and alter CP/M source files.
    [Show full text]