Modern C++

Brief history:

• Made in 1979 ("C With Classes")
• Revised in 1983 (Renamed to C++)
• Commercial release in 1985

• Mostly object-oriented features in this era
  • OOP, virtual functions, multiple inheritance, etc.

Brief history:

• Standardized for first time with C++98
  • STL (Standard Template Library) included
• C++03: minor updates to C++98
  • No changes to core, only addressed defects
• TR1 (Library Technical Report) in 2005
  • Draft document, not a standard

• Emphasis on template programming and data structures

Brief history:

• C++11 standard released
  • Major revision to standard
  • 13 years since anything really "new" (C++98)
• C++14: similar to C++03, fixes to C++11

Basically the rest of this talk's topic

Memory Management

• Better pointers known as "smart pointers"

  • unique_ptr<T>

  • shared_ptr<T>

  • weak_ptr<T>

• More like pointer wrapper
  • Reference counting
  • Overloaded = operators

Why it's awesome:

• Basically interchangeable with old pointers
  • Easy to update old code
• Maintains Resource Acquisition Is Initialization (RAII)
  • Reference-counted, not garbage-collected
  • Immediately release resources when no longer needed
  • Removes burden from programmer
    • i.e. never manually use "delete" again

Compare:

void someFunction()
{
  int* p = new int(5);
  // ...
  delete p;
}

Compare:

void someFunction()
{
  shared_ptr<int> p(new int(5));
  // ...
  //implicit ~p on function return
}

Type Safety

• New tools to increase code re-use:

  • auto

  • decltype

• Compiler deduces type of variables when possible
• Reduces verbosity of code

auto

• Used in place of type declaration
• e.g. instead of

  • int x = 5;

• use:

  • auto x = 5; //x is still int

decltype

• "Getter" for type
• Not realtime reflection, just deferred deduction
• Short example:

       int x = 5;
       decltype(x) y = x; //y is an int

More practical use:

• Write function once for multiple data types
  • Cleaner syntax than with templates

auto addSelf(auto x)
{
  return x + x;
}

//Compiler generates versions for both:
addSelf(5);
addSelf(std::string("Repeat"));

More practical use:

• Just straight-up saves on typing

std::vector<std:pair<int, int>>::iterator it = tuples.begin();

//identical to:

auto it = tuples.begin();