Thinking in C++ 2nd ed Volume 1 Revision 6

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polish your knowledge rather than present major challenges (presumably, you’ll find those on your own – or more likely, they’ll find you). Exercise solutions Solutions to selected exercises can be found in the electronic document The Thinking in C++ Annotated Solution Guide by Chuck Allison, available for a small fee from www.BruceEckel.com. [[ Note this is not yet available ]] Source code The source code for this book is copyrighted freeware, distributed via the Web site http://www.BruceEckel.com. The copyright prevents you from republishing the code in print media without permission. Although the code is available in a zipped file on the above Web site, you can also unpack the code yourself by downloading the text version of the book and running the program ExtractCode (from Volume 2 of this book), the source for which is also provided on the Web site. The program will create a directory for each chapter and unpack the code into those directories. In the starting directory where you unpacked the code you will find the following copyright notice: //:! :Copyright.txt Copyright (c) Bruce Eckel, 1999 Source code file from the book "Thinking in C++" All rights reserved EXCEPT as allowed by the following statements: You can freely use this file for your own work (personal or commercial), including modifications and distribution in executable form only. Permission is granted to use this file in classroom situations, including its use in presentation materials, as long as the book "Thinking in C++" is cited as the source. Except in classroom situations, you cannot copy and distribute this code; instead, the sole distribution point is http://www.BruceEckel.com 32 Thinking in C++ www.BruceEckel.com
(and official mirror sites) where it is available for free. You cannot remove this copyright and notice. You cannot distribute modified versions of the source code in this package. You cannot use this file in printed media without the express permission of the author. Bruce Eckel makes no representation about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty of any kind, including any implied warranty of merchantability, fitness for a particular purpose, or non-infringement. The entire risk as to the quality and performance of the software is with you. Bruce Eckel and the publisher shall not be liable for any damages suffered by you or any third party as a result of using or distributing software. In no event will Bruce Eckel or the publisher be liable for any lost revenue, profit, or data, or for direct, indirect, special, consequential, incidental, or punitive damages, however caused and regardless of the theory of liability, arising out of the use of or inability to use software, even if Bruce Eckel and the publisher have been advised of the possibility of such damages. Should the software prove defective, you assume the cost of all necessary servicing, repair, or correction. If you think you've found an error, please submit the correction using the form you will find at www.BruceEckel.com. (Please use the same form for non-code errors found in the book.) ///:~ You may use the code in your projects and in the classroom as long as the copyright notice is retained. Language standards Throughout this book, when referring to conformance to the ANSI/ISO C standard, I will generally just say ‘C.’ Only if it is necessary to distinguish between Standard C and older, pre- Standard versions of C will I make a distinction. Preface 33
Page 1 and 2: Thinking in C++ 2 nd edition Volume
Page 3 and 4: TICA18: July 29, 1999. Rewrote Chap
Page 5 and 6: TICA7, August 14, 1998. Strings cha
Page 7 and 8: http://www.microsoft.com/typography
Page 9 and 10: In Bruce Eckel President, MindView
Page 11 and 12: MindView Ad Space
Page 13 and 14: Dedication To the scholar, the heal
Page 15 and 16: 2: Making & Using Objects 87 The pr
Page 17 and 18: Type-safe linkage............. 323
Page 19 and 20: protected ............. 618 protect
Page 21 and 22: Preface Like any human language, C+
Page 23 and 24: So the short answer is: what isn’
Page 25 and 26: end up losing some portion of the a
Page 27 and 28: Chapters C++ is a language in which
Page 29 and 30: Chapter 5: Hiding the Implementatio
Page 31: existing type. In this chapter you
Page 35 and 36: note that the CD ROM is browser-bas
Page 37: Constantine, Lucy Lockwood, Tom Kef
Page 40 and 41: But computers are not so much machi
Page 42 and 43: the solution will run. There’s st
Page 44 and 45: So, although what we really do in o
Page 46 and 47: middle portion is not shown. If you
Page 48 and 49: necessary to achieve the functional
Page 50 and 51: more specific types of trash are de
Page 52 and 53: Shape +draw() +erase() +move() +get
Page 54 and 55: Thermostat Controls Cooling System
Page 56 and 57: BirdController What happens when fl
Page 58 and 59: doStuff(c); What’s happening here
Page 60 and 61: The second approach is to create ob
Page 62 and 63: Analysis and design The object-orie
Page 64 and 65: It’s often proposed that you “b
Page 66 and 67: Phase 1: What are we making In the
Page 68 and 69: eveal itself in the fullness of tim
Page 70 and 71: getting into too much detail too ea
Page 72 and 73: 2. Object assembly. As you’re bui
Page 74 and 75: Phase 4: Iteration This is the poin
Page 76 and 77: will still function. You need not f
Page 78 and 79: You’re already on the learning cu
Page 80 and 81: large, complex program, there’s n
Page 82 and 83:
first time, so it should not be mis
Page 84 and 85:
Performance issues A common questio
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alternatives. Even if you eventuall
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By reading this chapter first, you
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takes several steps. The transition
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variable in another object module,
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point of definition the compiler al
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In a function declaration, you give
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cause the preprocessor to search fo
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until link time, one possibility is
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This book will use Standard C++ (an
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included the header file but all th
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"Hello, world!" And now, finally, t
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int main() { // Specifying formats
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Simple file manipulation Standard I
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This upward compatibility from C to
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iostream object. It’s that simple
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it’s much easier if you have each
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so if you have an array a and you w
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while(in >> word) is what gets the
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Exercises Solutions to selected exe
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If you’ve never seen C before, th
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} x = y = z; // ... It turns out th
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In cfunc( ), the first if that eval
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to a nonzero value). Other conditio
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while(guess != secret) { // Compoun
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curly brace ‘{’. This is in con
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switch(selector) { case integral-va
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using namespace std; void removeHat
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: C03:AutoIncrement.cpp // Shows us
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The first part of the program defin
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: C03:Specify.cpp // Demonstrates t
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All the variables, and even the fun
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from dog, bird is four bytes away f
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: C03:PassByValue.cpp #include usi
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pointers later, but this is arguabl
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All possible combinations of basic
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variable was defined. That is, a sc
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int main() { //.. { // Begin a new
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using namespace std; int globe; voi
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want a value to be extant throughou
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} int i; // The data definition voi
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The const was taken from C++ and in
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Operators and their use This sectio
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Introduction to preprocessor macros
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Bitwise not produces the opposite o
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An interesting bit pattern: unsigne
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x = a * -b; but the reader might ge
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Common pitfalls when using operator
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checking to catch errors. Once you
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(4) Implicit type conversions, norm
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Can't use xp as an X* at this point
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Keyword Meaning xor_eq ^= (bitwise
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The struct declaration must end wit
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int main() { Structure3 s1, s2; Str
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You can see how much more readable
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Once you perform an assignment, the
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for(int i = 0; i < 10; i++) cout
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Even though func1( ) and func2( ) d
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#include using namespace std; int
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++, which “adds one to the pointe
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int* ip = a; P(*ip); P(*++ip); P(*(
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in all upper case. A common flag na
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punctuation are concatenated into a
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Defining a function pointer To defi
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Using a function pointer Once you d
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Make: an essential tool for separat
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multiple rules. Many make programs
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target1.exe: target2.exe: If you ju
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Declare: Declare.o $(CPP) $(OFLAG)D
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lectures, exercises, and guided sol
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values in your instance and print t
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flag. You will need to consult your
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to switch from some language that y
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:~ A tag name like CStashTag is gen
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delete []s->storage; } } ///:~ init
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new unsigned char[newBytes]; The ge
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: C04:CLibTest.cpp //{L} CLib // Te
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Each separate C file is a translati
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of all their function names. So ini
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C library converted to C++ // Decla
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You can see that all the member fun
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: C04:CppLibTest.cpp //{L} CppLib /
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What's an object Now that you’ve
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Object details A question that come
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most of the time, except when struc
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included throughout the system, the
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This will yield a true result, and
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end up “turning off” namespaces
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} void Stack::initialize() { head =
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Read file and store lines in the St
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etween what the user of the structu
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16. Modify Stash to use a vector as
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5: Hiding the Implementation A typi
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The second reason for access contro
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Although func( ) can access any mem
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void Z::initialize() { j = 99; } vo
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private: Holder* h; int* p; public:
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second argument) for n bytes past t
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Any object belonging to this class
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The examples in this book, however,
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void initialize(); void push(void*
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Here’s a simple example demonstra
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u.cleanup(); } ///:~ The only thing
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9. Copy the implementation and test
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This not only provides a single uni
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Now, when an object is defined, voi
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The destructor is called automatica
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eginning of a scope. If a construct
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However, some confusion may result
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pointer “down” (a relative term
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} storage = b; // Point to new memo
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Stack with constructors & destructo
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ut is not responsible for cleaning
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Now if you decide to add another el
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zz[i].print(); } ///:~ Notice that
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Safety during coding is a big issue
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7: Function Overloading & Default A
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Although function overloading is a
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int f(); This works fine when the c
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~Stash(); int add(void* element); v
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Both constructors are exercised in
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Although the member functions civil
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(outside all functions and classes)
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Placeholder arguments Arguments in
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Mem::Mem(int sz) { mem = 0; size =
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int main() { MyString s("My test st
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Notice that a call to ensureMinSize
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7. Create a new version of the Stac
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This provides safety and control in
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const). Storage must be allocated b
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situations, const means “a piece
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has the option of doing constant fo
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const int* const x = &d; // (1) int
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Function arguments & return values
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Returning by value as a const becom
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temporary X. However, f7( ) takes i
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that attempting to modify the desti
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Error: const temporary created by f
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void print(); }; Fred::Fred(int sz)
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until Chapter 10: static. The stati
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The “enum hack” in old code In
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non-const member function. Thus, an
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cq.lastQuote(); // OK //! cq.quote(
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} int main() { const Z zz; zz.f();
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char Comm::read(int index) const {
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9. Write a const pointer to a doubl
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assign via a void* (without a cast)
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In C, one of the ways to preserve e
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granted. In the un-parenthesized ve
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mixed together, so a problem like t
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space than the code generated to do
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Here, the class user never has dire
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void setWidth(int w) { width = w; }
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updateLocal(); return local.tm_sec;
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if(storage != 0) delete []storage;
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The Stack class makes even better u
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Inlines & the compiler To understan
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class Forward { int i; public: Forw
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interface and thereby making the cl
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Because there are actually two stat
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} } exit(1); inline void assure(std
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C++ is complicated enough without a
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second function, without the need f
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10: Name Control Creating names is
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function. C and C++ allow you to cr
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int i; public: X(int ii = 0) : i(ii
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static Obj b inside f( ) and the st
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all you’ve done is change the vis
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Creating a namespace The creation o
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names in an unnamed namespace, you
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Integer a, b, c; Integer divide(Int
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} #endif // USINGDECLARATION_H ///:
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is not very safe. Global data can b
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ws.print(); } ///:~ Here, the quali
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static const X x3; static const X x
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A static member function cannot acc
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int main() { //! Egg x(1); // Error
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zeroing of the storage occupied by
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definition for the Initializer init
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constructor, so you can tell if the
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} static Dependency1 dep1; return d
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across the various translation unit
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that when you give the argument wit
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your namespace into that function s
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a Mirror object, which it assigns t
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Although references also exist in P
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2. Once a reference is initialized
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} ///:~ The call to f(1) produces a
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how does the compiler know how to p
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farther to provide storage for the
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output for bigfun( ), you can see i
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When the local object goes out of s
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} }; int HowMany2::objectCount = 0;
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cout.width(width); cout
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Temporary objects Line 15 begins th
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cout
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Here’s an example: //: C11:NoCopy
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combined with the object dereferenc
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fp = &Simple2::f; } ///:~ In the de
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underlying implementation without a
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the member functions const and prov
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21. Create a simple class without a
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The difference is that the argument
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} }; i += rv.i; return *this; int m
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operator++(Integer& a); // Postfix:
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} Byte operator!() const { cout
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an example of all the operators you
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friend int operator=(const Integer&
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if(&left == &right) {/* self-assign
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} #define TRYC(OP) \ out
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%= right.b; return *this; } Byte& o
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} Byte b3 = 92; b1 = b2 = b3; int m
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ack the object that was changed. Th
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left-hand side of an equal sign. Th
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class ObjContainer { vector a; publ
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#include #include "../require.h" u
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pointer,” although the example sh
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around and calls operator( ) for th
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eturn i[x]; } friend ostream& opera
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Operator &= |= %= >>=
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When you create an operator=, you m
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} ~Dog() { cout
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it. However, if your object require
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: p(dog), houseName(house) { cout
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Before you make any modifications (
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Automatic operator= creation Becaus
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In this case, automatic type conver
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Reflexivity One of the most conveni
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using namespace std; class Stringc
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: C12:TypeConversionFanout.cpp clas
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(the creator of the class) or the u
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16. Add an int data member to both
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13: Dynamic Object Creation Sometim
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Object creation When a C++ object i
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... sometime later: obj->destroy();
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with a call to free( )). Just as a
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Before a pointer to that block is r
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If you have a memory leak in your p
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The other change is the replacement
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can prevent a memory leak (more ele
Page 571 and 572:
However, for the string pointers, i
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Now the array elements in q can be
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Another issue is heap fragmentation
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} free(m); class S { int i[100]; pu
Page 579 and 580:
} for(int i = 0; i < psize; i++) if
Page 581 and 582:
empty bracket syntax to indicate ar
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In both cases you’re handed the s
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When the program runs, it does not
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Notice that operator new only retur
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5. Repeat the above exercise, but a
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14: Inheritance & Composition One o
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int i; public: X() { i = 0; } void
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public: Y() { i = 0; } int change()
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The solution is simple: Call the co
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This makes built-in types act a lit
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#define CLASS(ID) class ID { \ publ
Page 603 and 604:
properly reverse the order of the c
Page 605 and 606:
in the new class. In the next chapt
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Name hiding comes into play here be
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~GameBoard() { cout
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ecause that function was not explic
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implementation hiding themselves, s
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} operator ifstream&() { return fil
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inherit privately, you’re “impl
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int read() const { return i; } void
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organic, evolutionary creature, rat
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your diagrams any way you find help
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Child object to a Parent& (if you c
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#include #include using namespace
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types inside the new type. Typicall
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class BusinessTraveler from Travele
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15: Polymorphism & Virtual Function
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quickly see the usefulness of this
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“narrow” that interface, but ne
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virtual void play(note) const { cou
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class Brass : public Wind { public:
Page 643 and 644:
The keyword virtual tells the compi
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pointer (the VPTR) into the structu
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instrument pointer brass object VPT
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call word ptr [bx+4] Finally, the s
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from the previous assembly-language
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instrument virtual void play() virt
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cout
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may be a common piece of code that
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virtual string sit() const { return
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the examples you’ve seen here, an
Page 663 and 664:
exists) and Dog, which no longer ex
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x = d2.f(); //! d2.f(s); // string
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int main() { Bird b; Cat c; Pet* p[
Page 669 and 670:
Order of constructor calls The seco
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that is called last. This is anothe
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int main() { Base1* bp = new Derive
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The only distinction occurs when yo
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ely on portions of an object that h
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} Object* peek() const { return hea
Page 681 and 682:
Creating containers that hold Objec
Page 683 and 684:
using namespace std; class Shape {
Page 685 and 686:
picture” of class relationships.
Page 687 and 688:
12. Create a model of a greenhouse
Page 689 and 690:
has no default constructor, so why
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16: Introduction to Templates Inher
Page 693 and 694:
} int pop() { return stack[top > 0
Page 695 and 696:
need an object, create it with new,
Page 697 and 698:
object-based hierarchy with its con
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code. The container no longer holds
Page 701 and 702:
In main( ), you can see how easy it
Page 703 and 704:
people see software as a service, a
Page 705 and 706:
} }; class Number { float f; public
Page 707 and 708:
}* head; public: Stack() : head(0)
Page 709 and 710:
changeable throughout the lifetime
Page 711 and 712:
#ifndef AUTOCOUNTER_H #define AUTOC
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The destructor for CleanupCheck doe
Page 715 and 716:
in the program, and you don’t nec
Page 717 and 718:
int main() { Stack ac; // Ownership
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array, copying the old array to the
Page 722 and 723:
of the underlying container) for an
Page 724 and 725:
} friend ostream& operator
Page 726 and 727:
} // Jump an iterator forward itera
Page 728 and 729:
void push(T* dat) { head = new Link
Page 730 and 731:
dereference operator performs the e
Page 732 and 733:
To create the end sentinel: iterato
Page 734 and 735:
} inflate(); storage[next++] = elem
Page 736 and 737:
int main() { { // To force destruct
Page 738 and 739:
class Square : public Shape { publi
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drawAll(p); cout
Page 742 and 743:
that, to acquire a library from a t
Page 744 and 745:
16. (Advanced) Modify PointerToMemb
Page 746 and 747:
Although many of these issues have
Page 748 and 749:
Begin and end comment tags A very i
Page 750 and 751:
void func(int a) { you immediately
Page 752 and 753:
The issue of where to put the openi
Page 754 and 755:
Use of require( ) and assure( ) The
Page 756 and 757:
also from the insights of friends i
Page 758 and 759:
elationship where it doesn’t exis
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22. Don’t use private inheritance
Page 762 and 763:
than global variables, although you
Page 764 and 765:
the heap, the catcher must know to
Page 766 and 767:
has enough information to deal with
Page 768 and 769:
768 Thinking in C++ www.BruceEckel.
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C Thinking in C: Foundations for Ja
Page 772 and 773:
Analysis & Design Extreme Programmi
Page 774 and 775:
mathematical determinism and the il
Page 776 and 777:
# compiler under dos: { all } # Obj
Page 778 and 779:
C07:MemTest.cpp C09:Cpptime.cpp C12
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Index -, 177 --, 178 !, 177 !=, 172
Page 782 and 783:
linking compiled C code with C++, 4
Page 784 and 785:
declaration, 93, 245, 256 analyzing
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static member, 378, 440, 477 using
Page 788 and 789:
Love, Tom, 777 lvalue, 170, 358 mac
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organization code, 260 code in head
Page 792 and 793:
short, 145 side effect, 170, 178 si
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assembly-language code generated by
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