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Data Type - Coggle Diagram

- - - - ex: String as a primitive type vs String as character arrays
  - - - Representation:- True or false
        
        True may be 1 or -1 or any other non zero value
        
        False is 0
        
        Computers cannot read data smaller than bits, therefore some languages provides options to read collections of bits
        
        Can have either True or False
        
        Some languages treat zero as true and all other values as 1
        
        One bit is enough but, many machines cannot read a single bit efficiently, therefore a word is used.
    - - A=65, 65 is called code point of 'A'
      - assignment of numbers to character set is called a code pages
      - character set is aggregate of all characters
      - ordering is collating sequence
      - types of coding
        
        8-bit ASCII
        
        ISO 8859-1
        
        Unicode
      - Code point is unique
      - single character as value
      - stored as numeric codes
    - - Integers
        
        Storage Representation
        
        Unsigned(no negative)
        
        Signed
        
        Two's Complement
        
        Sign-Magnitude(Cannot do arithmetics)
        
        One's Complement(Two representations of '0')
        
        Left most bit for the sign
        
        Operations on Integer Data
        
        Arithmetic
        
        Binary
        
        Unary
        
        Relation
        
        Assignment
        
        Bit Operation
        
        Number of bits requires, depends on the language implementation
      - Floating Point
        
        Representation
        
        IEEE Floating point standard 754 single precision(32-8 for exponent) and double precision (64-11 for exponent)
        
        Computer Representation
        
        Represented as Fractions and Exponents
        
        Same operations as Integer
        
        Types
        
        Float
        
        Double
        
        Double the size of float
        
        Always a signed number
        
        cons
        
        Some computers do not have hardware support. Software emulated float is slow to operate
        
        Numbers are rarely equal due to round -off
        
        no Boolean operations
        
        loss of accuracy
        
        Range is combination of range of fractional part and the exponents
      - Decimal/Fixed Point
        
        Fixed decimal points
        
        Some systems(that supports business systems) have hardware support, for others it's software emulated
        
        Data Stored
        
        Using BCD
        
        Decimal point is an attribute of the variable
        
        Advantages
        
        High Precision. (ex: Can represent 0.1)
        
        Disadvantages
        
        Restricted Range (no exponents)
        
        Wasting memory
        
        Stored as character strings(Storage waste because one bit per byte or may be t bit per byte)
      - Complex
        
        only few languages
        supports(python)
        
        Allows arithmetic
        
        represented as ordered pairs of floating point(for imaginary part, python use J)
        
        Symbol Table
        
        employed by language translator
        
        information about
        
        type
        
        scope level
        
        declaration or presence in source code
  - - - First field of every descriptor is the name of the type
      - types length in characters
      - Address of the first character
    - - Type name
      - max length
      - current length
      - address
      - Limited dynamic string of c and c++ do not need runtime descriptors
        
        End of string - '\n'
        
        max length - index values
      - max and current length stores at the header
    - - descriptor is same as static but current
        length is stored instead of length
      - can implement using linked lists
        
        string processing is slow but allocation
        and deallocation is fast
      - Stores four characters per block example
      - can implement using an array of pointers
        and each character stored in the heap
        
        faster string processing
      - Using adjacent cells and move the
        string when no adjacent cell
        
        faster string processing and less storage required
- - - - Row major
      - Column major
    - - rectangular
      - jagged
      - Longer allocation and deallocation
      - associative
  - - - flexible
    - - Static allocation. size known at compile time
      - efficient
    - - longer allocation and deallocation
      - flexibility
    - - space efficient
- - - - Hiding how a process worls
      - Programmers only need to know the
        inputs and the protocols
    - - Can create variables without knowing the structure
      - Group data types and hide declaration details
  - - - Type of operations available
      - Types of Data Allowed
      - Mechanisms Provided
        
        storing data
        
        controlling sequence which apply the operations on data
- - - - Static (Dynamic) type checking
      - Selection of correct operations when overloaded
      - Storage management
        
        size of the data block
        
        allocation
        
        lifetime
      - Storage representation
        
        bit representation
        
        attribute representation
        
        preferred location
        
        register
        
        stack
        
        heap
  - - - Elementary Data Objects
        
        an ordered set with least and greatest
        
        manipulates as a unit
        
        Not defined in terms of other types
        
        stored in fixed memory
      - Data Structures
        
        build using other types
        
        Building blocks are called components
        
        Variable memory space for values
    - - Hardware
        
        int
      - Language
        
        Standard libraries
        
        inbuilt
        
        other developers
      - user cunstructed
        
        Functions
        
        in line code sequences within the body of the program
        
        Library routines
- - - - Is a literal constant allowed to appear in more than one type definition.
      - Are enumeration values coerced to integer?
      - All of these design issues are related to type checking
    - - Relational operations (==, >,<)
      - Assignment
      - Operations such as successor and predecessor
        
        Successor : next value
        Predecessor : previous value.
    - - Readability
      - Reliability