C++: Intro

Super basics

• C++ is a compiled language
  • Source text is processed by compiler
  • Object files are produced
  • Linker combines object files
  • Executable program is produced for that system)
• ISO C++ defines two kinds of entities
  • Core language features (what lisp people call keywords)
  • STL components
• Statically typed: The type of every entity must be known to the compiler at its point of use.The type of an object determines the set of operations applicable to it.
• There is a main function in every program that should call everything else
• { } express grouping

Types, variables

• Declaration: a statement that introduces a name into the program, it specifies a type for the named entity
  • Type: defines a set of possible values and operations for an object
  • Object: some memory that holds a value of some type
  • Value: a set of bits interpreted according to a type
  • Variable: a named object
• Initialization
  • =
  • { }, which is aware of truncating conversions
    • Optionally = { }
  • const can’t be left uninitialized.
  • variables should not be left uninitialized. names should be introduced when needed.

  • ‘user-defined’ (non built-in) types can be set up to be implicitly initialized.

  • Explicit type statement in variable definition is not required when it can be deduced from the initializer using auto.
• Constants
  • const: I promise not to change this (compiler enforced). Used to specify interfaces.
  • constexpr: To be evaluated at compile time. Used to specify constants, read only memory (whatever that means) and performance
• Branching, sequencing, looping
  • if, switch
  • In declarations, there are declaration operators
    • [] means ‘array of’
    • * means ‘pointer to’
    • & means ‘reference to’
      • references can’t be made to refer to something different after initialization
      • * value of does not need to be used
    • T f(A)
  • In expressions
    • * means ‘value of’
    • & means ‘address of’
  • for( initialization ; check ; 'increment' )
  • or the ranged form for (auto : sequence)

User defined types

• struct organizes the elements of a type into a data structure. a struct
  • . accesses struct elements through a name or a reference
  • -> acceses struct elements through a pointer
  • members
    • data
    • function
    • type
• class
  • distinction between interface and implementation (public: and private: members)
• enum class - simple form of user defined type

Modularity

• declarations specify interfaces
• definitions specify implementation
• Separate compilation
  • header .h files with definitions
  • cpp .cpp files with declarations
• namespace groups names together to be accessed like namespace::name
• error handling: employ exceptions to inform users that an error ocurred
  • users can handle exceptions in try { } catch (exception) { } handlers
• Statements that are assumed to be true for a class are invariants and should be established in class constructors
• static_assert(constant_expr, message) will print message at compilation if constant_expr is not true**