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C++ by Choice
Florentin Picioroaga
IDS GmbH, Ettlingen, Germany
filo.rom@gmail.com
February 24, 2016
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 1 / 18
Overview
1 Motivation
2 Why C++?PopularityGeneral featuresStatic vs. Dynamic type systemSupports many paradigms
3 When C++?
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 2 / 18
Motivation
Why C++, when there are so many programming languages?
When C++? What is the best match (application, programminglanguage = C++)?
Not in the scope:
Why not C++?When not C++?
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 3 / 18
Motivation
Why C++, when there are so many programming languages?
When C++? What is the best match (application, programminglanguage = C++)?
Not in the scope:
Why not C++?When not C++?
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 3 / 18
Motivation
Why C++, when there are so many programming languages?
When C++? What is the best match (application, programminglanguage = C++)?
Not in the scope:
Why not C++?When not C++?
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 3 / 18
Popularity
Popularity is ,,the fact that something or someone is liked, enjoyed, or supported by
many people” (Cambridge)
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 4 / 18
Popularity
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 5 / 18
Popularity
Why is C++ popular?
Compatibility with C, no. 1 or 2 in the last 20 years:
source code compatibility
object code compatibility
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 6 / 18
General features
General-purpose undo mechanism with destructors
Undo for: memory, mutexes, opening filesRAII, implemented in C++ with constructors/destructorsGuaranteed to be executed even when an exception occurs, only for theobjects on the stackDeterministic finalization in contrast with GC systems
templates
generic programming (STL)TMP (Template Meta-Programming)
overloading
function objects, the basis of lambdas in C++11smart pointers
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 7 / 18
General features
General-purpose undo mechanism with destructors
Undo for: memory, mutexes, opening filesRAII, implemented in C++ with constructors/destructorsGuaranteed to be executed even when an exception occurs, only for theobjects on the stackDeterministic finalization in contrast with GC systems
templates
generic programming (STL)TMP (Template Meta-Programming)
overloading
function objects, the basis of lambdas in C++11smart pointers
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 7 / 18
General features
General-purpose undo mechanism with destructors
Undo for: memory, mutexes, opening filesRAII, implemented in C++ with constructors/destructorsGuaranteed to be executed even when an exception occurs, only for theobjects on the stackDeterministic finalization in contrast with GC systems
templates
generic programming (STL)TMP (Template Meta-Programming)
overloading
function objects, the basis of lambdas in C++11smart pointers
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 7 / 18
General features
General-purpose undo mechanism with destructors
Undo for: memory, mutexes, opening filesRAII, implemented in C++ with constructors/destructorsGuaranteed to be executed even when an exception occurs, only for theobjects on the stackDeterministic finalization in contrast with GC systems
templates
generic programming (STL)TMP (Template Meta-Programming)
overloading
function objects, the basis of lambdas in C++11smart pointers
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 7 / 18
Static vs. Dynamic type system
from formal logic we have two properties we can use to describe anyevaluation procedure: soundness and completeness
a sound type system is one that rejects all erroneous programs, and acomplete system accepts all correct programs
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 8 / 18
Static vs. Dynamic type system
from formal logic we have two properties we can use to describe anyevaluation procedure: soundness and completeness
a sound type system is one that rejects all erroneous programs, and acomplete system accepts all correct programs
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 8 / 18
Static vs. Dynamic type system
a programming language with a complete and unsound (static) typesystem has a fallback in the form of dynamic typing
dynamically typed means that types are attached to values at run time
statically typed means that types are checked at compile time, and aprogram that does not have a static type is rejected by the compiler
combined power of both type systems:
Mozilla Firefox: a core of statically-typed C++, with dynamically-typedJavaScript running the user interfacemany large video games, e.g. World of WarCraft: C++ and Lua
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 9 / 18
Static vs. Dynamic type system
is static or dynamic typing more convenient?
auto func = [] (int x) {
if (x >= 0) return 2*x;
return "negative number";
};
std::cout << func(2) << func(-1);
More convenient to write code in a dynamic language but moreconvenient to maintain a set of assumptions that cannot be violatedabout certain types.
does static typing prevent useful programs?
array t = { (1, 1), (true, true)}
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 10 / 18
Static vs. Dynamic type system
is static or dynamic typing more convenient?
auto func = [] (int x) {
if (x >= 0) return 2*x;
return "negative number";
};
std::cout << func(2) << func(-1);
More convenient to write code in a dynamic language but moreconvenient to maintain a set of assumptions that cannot be violatedabout certain types.
does static typing prevent useful programs?
array t = { (1, 1), (true, true)}
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 10 / 18
Static vs. Dynamic type system
is static or dynamic typing more convenient?
auto func = [] (int x) {
if (x >= 0) return 2*x;
return "negative number";
};
std::cout << func(2) << func(-1);
More convenient to write code in a dynamic language but moreconvenient to maintain a set of assumptions that cannot be violatedabout certain types.
does static typing prevent useful programs?
array t = { (1, 1), (true, true)}
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 10 / 18
Static vs. Dynamic type system
is static typings early bug-detection important?static typing catches bugs earlier, when the code is statically checked,compiled.bugs are easier to fix if discovered sooner, while the developer is stillthinking about the codethe programmer can rely on the compiler and focus atention elsewhere
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 11 / 18
Static vs. Dynamic type system
does static or dynamic typing lead to better performance?type tags do not exist at runtime, they take more space and slow downconstructorsfaster code since it does not need to perform type tests at run time
but if programmers in statically typed languages have to work aroundtype-system limitations, then those workarounds can erode thesupposed performance advantages
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 12 / 18
Static vs. Dynamic type system
does static or dynamic typing lead to better performance?type tags do not exist at runtime, they take more space and slow downconstructorsfaster code since it does not need to perform type tests at run timebut if programmers in statically typed languages have to work aroundtype-system limitations, then those workarounds can erode thesupposed performance advantages
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 12 / 18
Static vs. Dynamic type system
is static or dynamic typing better for prototyping?dynamic typing is often considered better for prototyping, no need todefine the types of variables, functions, and data structures when thosedecisions are in fluxsome part of the program would not type-check in a statically typedlanguage, but the rest of the program can run (e.g., to test the partsyou just wrote)
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 13 / 18
Static vs. Dynamic type system
is static or dynamic typing better for code evolution?dynamic typing is sometimes more convenient for code evolutionbecause we can change code to be more permissive (accept argumentsof more types) without having to change any of the pre-existing clientsof the code.
f(x) = return 2 * x
static type-checking is very useful when evolving code to catch bugsthat the evolution introduces. When we change the type of a function,all callers no longer type-check, which means the typechecker gives usa ,,to-do list” of all the call-sites that need to change
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 14 / 18
Supports many paradigms
procedural programming (functions and data separately)
free functions not belonging to any class
OOP (functions + data grouped in classes)
multiple inheritance
Generic programming
algorithms running for any data typealgorithms run as fast as an algorithm tuned for a specific type
functional programming
closures with imutable data
,,unsafe” programming
,,Trust the programmer”, the rational for C language.
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 15 / 18
Supports many paradigms
procedural programming (functions and data separately)
free functions not belonging to any class
OOP (functions + data grouped in classes)
multiple inheritance
Generic programming
algorithms running for any data typealgorithms run as fast as an algorithm tuned for a specific type
functional programming
closures with imutable data
,,unsafe” programming
,,Trust the programmer”, the rational for C language.
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 15 / 18
Supports many paradigms
procedural programming (functions and data separately)
free functions not belonging to any class
OOP (functions + data grouped in classes)
multiple inheritance
Generic programming
algorithms running for any data typealgorithms run as fast as an algorithm tuned for a specific type
functional programming
closures with imutable data
,,unsafe” programming
,,Trust the programmer”, the rational for C language.
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 15 / 18
Supports many paradigms
procedural programming (functions and data separately)
free functions not belonging to any class
OOP (functions + data grouped in classes)
multiple inheritance
Generic programming
algorithms running for any data typealgorithms run as fast as an algorithm tuned for a specific type
functional programming
closures with imutable data
,,unsafe” programming
,,Trust the programmer”, the rational for C language.
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 15 / 18
Supports many paradigms
procedural programming (functions and data separately)
free functions not belonging to any class
OOP (functions + data grouped in classes)
multiple inheritance
Generic programming
algorithms running for any data typealgorithms run as fast as an algorithm tuned for a specific type
functional programming
closures with imutable data
,,unsafe” programming
,,Trust the programmer”, the rational for C language.
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 15 / 18
When C++
Best suited for system applications:
must meet a constraint
really fast (simulation, computer generation of images)minimal powerdata layout
driverscommunication protocols, working with legacy systems
program size
static (including RTL)dynamic (image and working set size)
efficient communication with outside entities
HardwareOSescode in other languages (C)
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 16 / 18
References
Scott Meyers (2014)
Why C++ Sails When the Vasa Sank
Moscow C++ Party.
Dan Grossman (2015)
Programming Languages
University of Washington.
Ben Karel (2009)
Sound and Complete
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 17 / 18
Hope you enjoyed!
Florentin Picioroaga (IDS GmbH) C++ by Choice February 24, 2016 18 / 18
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