C++

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Contents 1 Overview 1.1 Benefits of C++ 2 Comparison with C 3 Important C++ Libraries 4 Memory Model 4.1 Parameter Passing

Overview

• an object orientated programming language
• invented by Bjarne Stroustrup in early 1980s at Bell Lab
  • first called "C with classes"
• constantly evolving, although now standardised
• design goals:
  • backwards compatible with ANSI C
  • object orientated capability
  • efficient running speed
    • use native code and little/no runtime error checking
  • simple syntax

• C++ provides
  • Data Types
  • Functions
  • Classes

Benefits of C++

• large installed code base
• available on many platforms
• powerful object orientated and abstraction features
• interface easily with hardware and/or other languages
• efficient

Comparison with C

• C++ is more type safe than C
• C++ supports objects and object orientated concepts
• makes other improvements to C language

Important C++ Libraries

• Standard C Library
  • low-level functions for manipulating strings, arrays, input-output, and math
  • not object orientated
  • cctype - provides functions that classify character values
  • cwtype - provides functions that classify wide character values
  • cstring - functions for C strings
• Standard C++ Library
  • incorporates many classes from Standard C Library
• STL (Standard Template Library)
  • containers and generic algorithms

Memory Model

• local variables normally allocated on the stack
  • created when reached in the function
  • destroyed when no longer in scope (e.g. when function returns)
  • includes primitive data types, pointers, arrays, and objects

• entities can be created on the heap using the "new" operator at runtime
  • dynamic memory allocation
  • object remains on heap until program ends, or programmer removes it
  • objects can be removed from the heap by using the "delete" operator

Parameter Passing

• when a variable is assigned to another one
  • copied by value
    • a completely new copy of the entity is made
    • this includes objects
• to provide reference semantics for assignment:
  • pointer and reference data types are provided