1.1.2 Definitions - Data and information, Data type, Data object, ADT, Data Structure

1.1.2 Definitions:

Data: Data is a collection of facts, such as values or measurements

• It can be numbers, words, measurements, observations or even just descriptions of things.
• Data is a raw and unorganized fact that required to be processed to make it meaningful. Data can be simple at the same time unorganized unless it is organized.
• Data is always interpreted, by a human or machine, to derive meaning. So, data is meaningless. Data contains numbers, statements, and characters in a raw form.
• Data can be qualitative or quantitative.
• Qualitative data is descriptive information (it describes something)
• Quantitative data is numerical information (numbers).

Information:

• Information is a set of data which is processed in a meaningful way according to the given requirement. Information is processed, structured, or presented in a given context to make it meaningful and useful.
• It is processed data which includes data that possess context, relevance, and purpose. It also involves manipulation of raw data.
• Information assigns meaning and improves the reliability of the data. It helps to ensure undesirability and reduces uncertainty. So, when the data is transformed into information, it never has any useless details.

Key Differences Between Data and Information

• Data is a raw and unorganized fact that is required to be processed to make it meaningful whereas Information is a set of data that is processed in a meaningful way according to the given requirement.
• Data does not have any specific purpose whereas Information carries a meaning that has been assigned by interpreting data.
• Data alone has no significance while Information is significant by itself.
• Data never depends on Information while Information is dependent on Data.
• Data measured in bits and bytes, on the other hand, Information is measured in meaningful units like time, quantity, etc.
• Data can be structured, tabular data, graph, data tree whereas Information is language, ideas, and thoughts based on the given data.

Data Type:

• A data type is a well-defined collection of data with a well-defined set of operations on it. A Data type in any programming language refers to the type of Data a variable declared in that language can hold.
• Every programming language has its own data type.

The basic data types in C are:

• int  - an integer
• float - a single precision floating point number
• char  - a character in C character set
• double- a double precision floating point number

Example:

int i = 100;  
char name = "R";  
Above I have created two variables; the first is an int and can contain only integer values. The second is a char and can contain only alphanumeric text values. Similarly, there are more such data types available in C.

Data Object:

• A Data object represents a container for data values, a place where data values may be stored and later retrieved.
• It is also defined as, a runtime grouping of one or more pieces of data in a virtual computer.
• A Location in memory with an assignment name in the actual computer.

Data objects can be:

1. at program execution- Programmer-defined - (example variables, constant, arrays, files etc) 
2. not directly accessible to programmer- system defined- run time storage, stacks, file buffers, free space lists. 

Data values can be: 

1. Single number 
2. Pointer to other objects and characters.

A Data Object is elementary if it contains a data value that is always manipulated as a unit.

ADT:

In computer science, an abstract data type (ADT) is a mathematical model for a certain class of data structures that have similar behavior; or for certain data types of one or more programming languages that have similar semantics. An abstract data type is defined indirectly, only by the operations that may be performed on it and by mathematical constraints on the effects (and possibly cost) of those operations. 

An abstract data type includes:

o   Declaration of data.

o   A structure defined by a set of rules that put components together.

o   A set of operations and encapsulation of data.

Definition:  An abstract data type is defined as a mathematical model of the data objects that make up a data type as well as the functions that operate on these objects. A set of data values and associated operations that are precisely specified independent of any particular implementation. 

Example: The abstract data type Set has the operations EmptySet(S), Insert(x,S), Delete(x,S), Intersection(S1,S2), Union(S1,S2), Member(x,S), Equal(S1,S2), Subset(S1,S2). 

A data structure is an actual implementation of a particular abstract data type.

Uses of ADT: -

1. It helps to efficiently develop well designed program
2. Facilitates the decomposition of the complex task of developing a software system into a number of simpler subtasks
3. Helps to reduce the number of things the programmer has to keep in mind at any time
4. Breaking down a complex task into a number of earlier subtasks also simplifies testing and debugging

Data Structure: 

A data structure is a way of organizing data that considers not only the items stored, but also their relationship to each other.

OR

Data Structure is a specialized format for storing data so that the data’s can be organized in an efficient way.

Advance knowledge about the relationship between data items allows designing of efficient algorithms for the manipulation of data.