Structures

Types

Basic Types

variables types that only have one section of memory dedicated to it

• These types are common in every language and hold numeric values.
• Here is the list of common basic types, in increasing memory usage:
  • boolean - true or false
  • char - a character
  • byte - a binary value
  • short integer - a small integer value, about [-255,255]
  • integer - an integer value, about [-32000, 32000]
  • long - a large integer value, about [-2 million, 2 million]
  • floating point - a decimal value, about [-2*10^7, 2*10^7] with 3 significant digits
  • double floating point - a decimal value with twice the precision of a floating point, about [-2*10^14, 2*10^14] with 6 significant digits
• Other languages call these primitive of simple types.

Simple Types

a basic type that's memory is totally dedicated to a numeric value

Complex type

a basic type that's memory is has different sections for different values

• A bit hard to understand, but bear with. The float needs about four bytes of memory. Three of those bytes holds a numeric value, e.g. 123, and one byte for a significant digit, e.g. -2. The computer interprets it like this 123*10^-2 = 1.23.
• However other types, basically non decimals, have their bytes totally dedicated to numeric values.

Structure Types

types that are made of basic types and/or structured types

• These are often user defined--which you take classes to learn how to write them--but some are so useful they are predefined like string or array.

Memory Type

a type that involved memory locations of other types

• Memory types go under the guises of pointer and reference. Also each language has different rules for how memory types are. These often don't exist in simple languages.
• These types aren't often touched until CS2.
• There are two types of these:
  • reference - refers to the actual memory location of another variable, anything done to the reference is done to the variable
  • pointer - refers to a type of memory location, e.g. ints only

User Define Types

Enumeration

a simple type which defines a set of variables to have integer values

• This is like defining a set of constant integers.
• This is very useful with switch statements to process different circumstances.

Simple Structure

a type which has a set of various data members, which are often accessible with the dot notation

• Simple structures are also know as struct and type.
• These are useful for processing a small set of values associated together, e.g. the information on a ID card

Class

a complex structure which has a state, i.e. data members, which often cannot be accessed and member functions, which are often accessed with the dot notation

• The most powerful structure, mwha mwha mwhaaaa. The data members represent a state for the class. These are often untouchable to users.
• The status of the data members are changed by operators, which are functions specifically associated with the class.
• Data members are also know as variable member, or instance variables.
• Member functions are also know as operators and methods.
• Again this is a powerful type which you may use, but will not create one on your own until latter levels of computer science.

Object

an instance of a class

• Often classes and objects are hard to conceptualize. Other people use the blueprint analogy, but I like this one better. A class is like the "int" in declaring a new variable, and the object is the variable you declare like "num".

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