Data Structures Pt.1

Data Structures Pt.1

1. Dynamic Data Structures

   • Do not have a limited size and can expand or shrink as needed during program execution.
     • Disadvantages: Tend to be more complex to implement. Needs to use pointers which are very complex.
     • Advantages: Memory Efficient, Only uses as much space as needed.

2. Static Data Structures

   • The size of the data structure is set at the beginning of the program and cannot be changed.
     • Advantages: Easier to program and you always know how much space they will take up.
     • Disadvantages: This is very limiting because it means you have to know in advance how large the data structure needs to be.
   • Array
     • Holds several items of the same data type. They are all grouped under one identifier.
     • Individual items are accessed using an index.
     • Stored contiguously in computer memory. The items are stored within the elements of the array.
   • Why Use Arrays?
     • To find each piece of data it has to be referred to by a different variable name
     • This means that similar pieces of data can be scattered all over memory.
     • Data stored in a computer is stored at any location in memory that the computer decides to use.

3. Files

   • All information about an entity is a File. All information referring to a particular student is called their Record. A number of records make up a file.
   • A field is an individual characteristic or property of an entity.
   • Each row represents a Record. Each column represent a Field.

4. Tuples & Lists

   • Similar to one-dimensional array. However they cannot be edited once they have been assigned, and they can contain values of different data types.
   • A List is a cross between an array and a tuple. It can hold a range of data types. Their elements can be edited once they have been initiated.