Unit 1 notes
Introduction to programming language:
A programming language is a set of instructions and syntax used to create software
programs. Some of the key features of programming languages include:
1. Syntax: The specific rules and structure used to write code in a programming
language.
2. Data Types: The type of values that can be stored in a program, such as
numbers, strings, and Booleans.
3. Variables: Named memory locations that can store values.
4. Operators: Symbols used to perform operations on values, such as addition,
subtraction, and comparison.
5. Control Structures: Statements used to control the flow of a program, such as
if-else statements, loops, and function calls.
6. Libraries and Frameworks: Collections of pre-written code that can be used
to perform common tasks and speed up development.
7. Paradigms: The programming style or philosophy used in the language, such
as procedural, object-oriented, or functional.
A programming language is a formal language that specifies a set of instructions for
a computer to perform specific tasks. It’s used to write software programs and
applications, and to control and manipulate computer systems. There are many
different programming languages, each with its own syntax, structure, and set of
commands. Some of the most commonly used programming languages include Java,
Python, C++, JavaScript, and C#. The choice of programming language depends on
the specific requirements of a project, including the platform being used, the
intended audience, and the desired outcome.
Characteristics of a programming Language –
• A programming language must be simple, easy to learn and use, have good
readability, and be human recognizable.
• Abstraction is a must-have Characteristics for a programming language in
which the ability to define the complex structure and then its degree of
usability comes.
• A portable programming language is always preferred.
, • Programming language’s efficiency must be high so that it can be easily
converted into a machine code and its execution consumes little space in
memory.
• A programming language should be well structured and documented so that it
is suitable for application development.
• Necessary tools for the development, debugging, testing, maintenance of a
program must be provided by a programming language.
• A programming language should provide a single environment known as
Integrated Development Environment(IDE).
• A programming language must be consistent in terms of syntax and semantics.
Advantages of programming languages:
1. Increased Productivity: Programming languages provide a set of
abstractions that allow developers to write code more quickly and efficiently.
2. Portability: Programs written in a high-level programming language can run
on many different operating systems and platforms.
3. Readability: Well-designed programming languages can make code more
readable and easier to understand for both the original author and other
developers.
4. Large Community: Many programming languages have large communities
of users and developers, which can provide support, libraries, and tools.
Disadvantages of programming languages:
1. Complexity: Some programming languages can be complex and difficult to
learn, especially for beginners.
2. Performance: Programs written in high-level programming languages can
run slower than programs written in lower-level languages.
3. Limited Functionality: Some programming languages may not have built-in
support for certain types of tasks or may require additional libraries to perform
certain functions.
4. Fragmentation: There are many different programming languages, which
can lead to fragmentation and make it difficult to share code and collaborate
with other developers.
Elements of programming language:
,There are four essential ingredients. These are, Variables, Conditionals, Loops and
Functions.
Variables are used to store data. They are simply labels used to reference and keep
track of a directly-inserted value or some expression that evaluates to a value. All
that matters is that the value in question is used to represent data. They can be
primary and composite.
Primitives are elementary values. They are used to express quantities and qualities
of things and most often, their literals have no underlying structure. For all our
purposes we’ll simply need, Numbers, Strings and Booleans.
Composites are containers which can have for elements, primitives and even other
composites. Lists and Associations (Dictionaries and Mappings) are to me all you
need in this category. They implement different element-identification
schemes, index-based and key-value pairs, respectively.
Conditionals and Loops help us alter the execution flow from its top-bottom default
and steer it through complex decision trees and iterative tasks. These are pretty
standard construction in all languages and being acquainted with if-, switch-, while-
and for-statement is sufficient for all uses.
Functions package a feature that applies a certain transformation to data or manages
a certain resource (like a file or the screen) to transmit data through it. A function
allows us to bundle a set of instructions into a callable block. It is the realization of
an IPO (Input-Processing-Output) type of structure which consumes data transform
it and then returns the result.
Programming language theory:
Programming language theory (PLT) is a branch of computer science that deals with
the design, implementation, analysis, characterization, and classification of
programming languages and their individual features. It falls within the discipline of
computer science, both depending on and affecting mathematics, software
engineering and linguistics. It is a well-recognized branch of computer science, and
an active research area, with results published in numerous journals dedicated to
PLT, as well as in general computer science and engineering publications.
In some ways, the history of programming language theory predates even the
development of programming languages themselves. The lambda calculus,
developed by Alonzo Church and Stephen Cole Kleene in the 1930s, is considered
by some to be the world’s first programming language, even though it was intended
to model computation rather than being a means for programmers to describe
algorithms to a computer system.
, The lowercase Greek letter λ (lambda) is an unofficial symbol of the field of
programming-language theory. Lambda calculus is based on minimal construction
of abstractions(functions) and substitution(application)
Bohm jacopini theorem:
The types of programs we've written so far for the Turing machine are what are
usually called non-structured. This type of code is generally very difficult to read
and understand. It really has very little to do with how we program in a modern high
level (further abstracted from the machine) programming language. Corrado Böhm
and Giuseppe Jacopini showed in 1966 that any non-structured program can be
rewritten by combining three techniques: sequence, selection, and repetition (or
loop). This is something we're familiar with and is how we've been writing our
algorithms since we started, but now we can see the connection between the Turing
machine and what we've been doing.
The structured program theorem, also called the Böhm–Jacopini theorem,[1][2] is a
result in programming language theory. It states that a class of control-flow graphs
(historically called flowcharts in this context) can compute any computable function
if it combines subprograms in only three specific ways (control structures). These
are
1. Executing one subprogram, and then another subprogram (sequence)
2. Executing one of two subprograms according to the value of a boolean
expression (selection)
3. Repeatedly executing a subprogram as long as a boolean expression is true
(iteration)
The structured chart subject to these constraints may however use additional
variables in the form of bits (stored in an extra integer variable in the original proof)
in order to keep track of information that the original program represents by the
program location. The construction was based on Böhm's programming language
P′′.
To review, sequence performs some operations S1; S2 meaning perform S1; then
perform S2.
Introduction to programming language:
A programming language is a set of instructions and syntax used to create software
programs. Some of the key features of programming languages include:
1. Syntax: The specific rules and structure used to write code in a programming
language.
2. Data Types: The type of values that can be stored in a program, such as
numbers, strings, and Booleans.
3. Variables: Named memory locations that can store values.
4. Operators: Symbols used to perform operations on values, such as addition,
subtraction, and comparison.
5. Control Structures: Statements used to control the flow of a program, such as
if-else statements, loops, and function calls.
6. Libraries and Frameworks: Collections of pre-written code that can be used
to perform common tasks and speed up development.
7. Paradigms: The programming style or philosophy used in the language, such
as procedural, object-oriented, or functional.
A programming language is a formal language that specifies a set of instructions for
a computer to perform specific tasks. It’s used to write software programs and
applications, and to control and manipulate computer systems. There are many
different programming languages, each with its own syntax, structure, and set of
commands. Some of the most commonly used programming languages include Java,
Python, C++, JavaScript, and C#. The choice of programming language depends on
the specific requirements of a project, including the platform being used, the
intended audience, and the desired outcome.
Characteristics of a programming Language –
• A programming language must be simple, easy to learn and use, have good
readability, and be human recognizable.
• Abstraction is a must-have Characteristics for a programming language in
which the ability to define the complex structure and then its degree of
usability comes.
• A portable programming language is always preferred.
, • Programming language’s efficiency must be high so that it can be easily
converted into a machine code and its execution consumes little space in
memory.
• A programming language should be well structured and documented so that it
is suitable for application development.
• Necessary tools for the development, debugging, testing, maintenance of a
program must be provided by a programming language.
• A programming language should provide a single environment known as
Integrated Development Environment(IDE).
• A programming language must be consistent in terms of syntax and semantics.
Advantages of programming languages:
1. Increased Productivity: Programming languages provide a set of
abstractions that allow developers to write code more quickly and efficiently.
2. Portability: Programs written in a high-level programming language can run
on many different operating systems and platforms.
3. Readability: Well-designed programming languages can make code more
readable and easier to understand for both the original author and other
developers.
4. Large Community: Many programming languages have large communities
of users and developers, which can provide support, libraries, and tools.
Disadvantages of programming languages:
1. Complexity: Some programming languages can be complex and difficult to
learn, especially for beginners.
2. Performance: Programs written in high-level programming languages can
run slower than programs written in lower-level languages.
3. Limited Functionality: Some programming languages may not have built-in
support for certain types of tasks or may require additional libraries to perform
certain functions.
4. Fragmentation: There are many different programming languages, which
can lead to fragmentation and make it difficult to share code and collaborate
with other developers.
Elements of programming language:
,There are four essential ingredients. These are, Variables, Conditionals, Loops and
Functions.
Variables are used to store data. They are simply labels used to reference and keep
track of a directly-inserted value or some expression that evaluates to a value. All
that matters is that the value in question is used to represent data. They can be
primary and composite.
Primitives are elementary values. They are used to express quantities and qualities
of things and most often, their literals have no underlying structure. For all our
purposes we’ll simply need, Numbers, Strings and Booleans.
Composites are containers which can have for elements, primitives and even other
composites. Lists and Associations (Dictionaries and Mappings) are to me all you
need in this category. They implement different element-identification
schemes, index-based and key-value pairs, respectively.
Conditionals and Loops help us alter the execution flow from its top-bottom default
and steer it through complex decision trees and iterative tasks. These are pretty
standard construction in all languages and being acquainted with if-, switch-, while-
and for-statement is sufficient for all uses.
Functions package a feature that applies a certain transformation to data or manages
a certain resource (like a file or the screen) to transmit data through it. A function
allows us to bundle a set of instructions into a callable block. It is the realization of
an IPO (Input-Processing-Output) type of structure which consumes data transform
it and then returns the result.
Programming language theory:
Programming language theory (PLT) is a branch of computer science that deals with
the design, implementation, analysis, characterization, and classification of
programming languages and their individual features. It falls within the discipline of
computer science, both depending on and affecting mathematics, software
engineering and linguistics. It is a well-recognized branch of computer science, and
an active research area, with results published in numerous journals dedicated to
PLT, as well as in general computer science and engineering publications.
In some ways, the history of programming language theory predates even the
development of programming languages themselves. The lambda calculus,
developed by Alonzo Church and Stephen Cole Kleene in the 1930s, is considered
by some to be the world’s first programming language, even though it was intended
to model computation rather than being a means for programmers to describe
algorithms to a computer system.
, The lowercase Greek letter λ (lambda) is an unofficial symbol of the field of
programming-language theory. Lambda calculus is based on minimal construction
of abstractions(functions) and substitution(application)
Bohm jacopini theorem:
The types of programs we've written so far for the Turing machine are what are
usually called non-structured. This type of code is generally very difficult to read
and understand. It really has very little to do with how we program in a modern high
level (further abstracted from the machine) programming language. Corrado Böhm
and Giuseppe Jacopini showed in 1966 that any non-structured program can be
rewritten by combining three techniques: sequence, selection, and repetition (or
loop). This is something we're familiar with and is how we've been writing our
algorithms since we started, but now we can see the connection between the Turing
machine and what we've been doing.
The structured program theorem, also called the Böhm–Jacopini theorem,[1][2] is a
result in programming language theory. It states that a class of control-flow graphs
(historically called flowcharts in this context) can compute any computable function
if it combines subprograms in only three specific ways (control structures). These
are
1. Executing one subprogram, and then another subprogram (sequence)
2. Executing one of two subprograms according to the value of a boolean
expression (selection)
3. Repeatedly executing a subprogram as long as a boolean expression is true
(iteration)
The structured chart subject to these constraints may however use additional
variables in the form of bits (stored in an extra integer variable in the original proof)
in order to keep track of information that the original program represents by the
program location. The construction was based on Böhm's programming language
P′′.
To review, sequence performs some operations S1; S2 meaning perform S1; then
perform S2.
