C standard library

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C standard library
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History

• Standardization of c started in 1989 and
  finished at the end of 1997.
• The result was a reference manual with
  approximately 750 pages, published by ISO.
• The standard has the title
• Information technology programming languages
  C

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Standard is an important milestone

• 1- it defines the exact content and behavior of
  C
• 2- it makes it easier to teach C
• 3- to use C in applications
• 4- port C programs to different platforms

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New language features

• C is not the same as 5 years ago
• All compilers are not able to provide all
  features.

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Templates

• Almost all parts of the STL are written as
  templates
• Templates are functions or classes written for
  one or more types not yet specified.
• Keyword typename

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• template classltTgt
• inline const T max (const T a, const T
  b)
• return a lt b ? b a
• template ltclass Tgt
• class myClass
• typename TsubType ptr
• myClassltintgt x1

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Explicit initialization for fundamental types

• int i1 //undefined value
• int i2 int() //initialized with zero

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Exception handling

• Handling exceptions without polluting your
  function interface
• If you encounter an unexpected situation , you
  can stop the usual data processing by throwing an
  exception
• The throw statement starts a process called stack
  unwinding.

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namespaces

• As I completely discussed first session

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Type bool
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Keyword explicit

• class Stack
• explicit Stack (int size)
• .
• Stack s
• s 40

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New operators for type conversion

• static_cast
• float x
• cout ltlt static_castltintgtx
• dynamic_cast
• Allows to downcast a polymorphic type to its real
  static type . This is the only cast that is
  checked at runtime.
• const_cast
• Adds or removes the constness of an operator
• reinterpret_cast

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• class car
• class cabriolet public car
• ..
• car cp
• cabriolet p dynamic_castltcabrioletgt(cp)

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Initialization of const static members

• class myClass
• static const int num 100
• int elements num // OK
• ..

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Definition of main

• There are only two correct and portable versions
  of main( )
• int main( )
• int main (int argc, char argv)

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General concepts

• The namespace std
• The names and formats of header files
• The general concepts of errors and exception
  handling
• A brief introduction to allocators

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Namespace std

• The use of std for all identifiers of the C
  standard library was introduced during the
  standardization
• But in old header files identifiers are defined
  in global scope

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Header files

• Old extensions .h .hpp .hxx
• New no extension
• Inside new headers all identifiers inside
  namespace std
• C derived headers added c at the beginning of
  their name

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Error exception handling

• Every part of standard library has its own
  exceptions like STL , String
• All exceptions thrown from the language or the
  library are derived from the class exception
• The standard exception classes can be divided
  into 3 groups
• 1- exceptions for language support
• 2- exceptions for the C standard library
• 3- exceptions for errors outside the scope of a
  program

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More about exceptions

• We can throw standard exceptions
• We derive standard exception classes
• class myProblem public stdexception
• ..
• String s
• .
• throw out_of_range(s)

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Allocators

• The C standard library uses in several places
  special objects to handle the allocation and
  deallocation of memory.
• Such objects are called allocators.

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AYLOOZ

• Alireza Fathi