And Under the hood of the of C++Builder IDE and compilers More information: http://embt.co/2016cbootcamp

1. David Millington, Bruneau Babet, Patrick Scheller
David.Millington@embarcadero.com
Day 3:
Under the hood of the
C++Builder IDE and Compilers

2. David Millington
David.Millington@embarcadero.com
Day 3:
C++11 Language Deep Dive

3. Iterators
it = collection.begin();
Loop until not equal to end() – end() points to one past the last item.
Increment (eg ++ to inc by one) or decrement to move where in the range
the iterator is pointing to.
for (std::vector<int>::const_iterator it =
items.begin(); it != items.end(); it++)
Pointer semantics: ‘dereference’ with * or ->, like a real pointer to
something.
int i = *it; // where it is an iterator in to a collection of ints

4. Lambdas
Anonymous functions, written inline, capture variables, behave like objects
(can assign to a variable.)
[] The variable or capture list
() The argument list
{} Code
[n](int& i, this) { return i + n == this->foo; }

5. Lambdas
auto f = [&n](int i)
{ return i + n };
Making the simplest lambda
[](){}
a method that captures nothing, is passed no arguments, and does nothing.
• Neat and readable
• Inline in code
• Inlineable and performant
• Capture variables by value or reference
• Behave like an object

6. Smart Pointers
No:
Foo* foo = new Foo();
__try {
//
} __finally {
delete foo;
}
Yes:
{
unique_ptr<Foo> foo(
new Foo());
}
^- foo is freed

7. Smart Pointers
Using boost? Move to shared_ptr (very familiar!) and unique_ptr instead of
scoped_ptr
In general, already using them or not:
• Use unique_ptr where possible
• Use shared_ptr not out of ease but when you want to share
• Don’t expect automatic threadsafety apart from +/- refcount
• Use shared_ptr<Foo> p = make_shared<Foo>; and
make_unique<T> if available - http://stackoverflow.com/questions/17902405/
how-to-implement-make-unique-function-in-c11
• Never write new or delete

8. Old vs Newstd::vector<int> items;
items.push_back(1);
items.push_back(2);
items.push_back(5);
std::map<int, std::wstring> map;
map[1] = L"One";
map[2] = L"Two";
map[3] = L"Three";
// Demonstrate an algorithm
for_each(items.begin(), items.end(), VectorMapFunctor(map));
// Print all vector items
for (std::vector<int>::const_iterator it = items.begin();
it != items.end(); it++) {
std::wcout << *it << std::endl;
}
// Create and do something with a Foo, then destroy it
Foo* foo = new Foo();
Test(foo);
delete foo;
std::vector<int> items {1, 2, 5};
std::map<int, std::wstring> map {
{1, L"One"},
{2, L"Two"},
{3, L"Three"}
};
// Demonstrate an algorithm - now use a lambda
for_each(items.begin(), items.end(),
[&map](int n) { std::wcout << map[n] << std::endl; });
// Print all vector items
for (auto i : items) {
std::wcout << i << std::endl;
}
// Create and do something with a Foo, then destroy it
std::unique_ptr<Foo> foo(new Foo());
Test(*foo);
Definition not included –
too much code already

9. Example extensions
class Foo {
private:
int m_Bar;
void SetBar(int i) { m_Bar = i);
public:
__property Bar { read = m_Bar, write = SetBar }
}
Also closures (object instance + method pointer); RTTI; etc.

10. Compilers
Classic:
• bcc32, descendant of Turbo C++, Win32/OSX
New / Clang enhanced:
• Based on Clang, with extensions
• Started with Clang 3.1 & Win64, now 3.3 with many backports, next 3.9
• Win32, Win64, iOS32/64 (ARM), Android ARM, Linux (x64, next release)…
Free:
• The Clang Win32 compiler
• https://www.embarcadero.com/free-tools/ccompiler

11. Q&A and Resources – C++ talk next up!
• Basics: Books! http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list and forums like the C
++ G+ group: https://plus.google.com/u/0/communities/116007775542700637383 (general C++) or https://
plus.google.com/communities/118315259185736124693 (C++Builder)
• C++ / STL: http://cppreference.com
• Auto: http://thbecker.net/articles/auto_and_decltype/section_01.html
• Lambdas: http://www.drdobbs.com/cpp/lambdas-in-c11/240168241
• Smart pointers: http://www.acodersjourney.com/2016/05/top-10-dumb-mistakes-avoid-c-11-smart-pointers/
• C++ Builder
• http://docwiki.embarcadero.com/RADStudio/Berlin/en/C++11_Language_Features_Compliance_Status
• http://docwiki.embarcadero.com/RADStudio/Berlin/en/C++11_Features_Supported_by_RAD_Studio_Clang-
enhanced_C++_Compilers
https://www.facebook.com/cppbuilder and https://twitter.com/EmbarcaderoTech
Under the hood of the C++ compiler and IDE:
a conversation with Patrick Scheller and Bruneau Babet
is up next, right after the Q&A!