High Level Language Programming

High Level Language Programming

An Overview of the Programming Language C++

Data Abstraction

Constants and variables possess a data type**; e.g., integers, characters, real numbers
Data type specifies what to represent but hides the actual representation from the programmer

Computation Abstraction

Operations are higher-level than individual machine language instructions
Data type identifies actual operations; e.g., real addition or integer addition
Procedural abstraction: Programmers may introduce higher-level operations using functions and procedures

** The term "type" can be applied to any identifier in a programming language and is NOT restricted to only data elements; in fact, every "first class object" in a progamming language has an associated type. A better definition is:

type

Is a tuple composed of

the set of permitted objects that may be associated with an identifier, and
the set of applicable operations over those objects.

Type: Integer

Objects

Operations

The set of integers from 0 to maxint

Addition (+)

Subtraction (-)

Multiplication (*)

Integer Division (/)

Type: variable

Objects

Operations

An identifier of memory location that can contain a representation of a specific type

The same operations as are permitted for the associated type

assignment (:=)

Type: program

Objects

Operations

A set of executable statements and function definitions

run

Type names include not only integer, real, and character, but also array, function, program, label, etc. Some types are defined by the location of a language element in a program and not by specific declaration.

The History of C++
Bjarne Stroustrup's homepage