ASANTE
KWAME PAAPA
SUMMARY
OF CHAPTER 13- PROGRAMMING LANGUAGES AND PROGRAM DEVELOPMENT.
DEFINITION
OF COMPUTER PROGRAM AND PROGRAMMING LANGUAGE.
A
computer can be explained as any electronic device operating under the
control of instructions, stored in its own memory. A
language is a system of communication. A programming language consists of all
the symbols, characters, and usage rules that permit people to communicate with
computers. There are at least several hundred, and possibly several thousand
different programming languages. Some of these are created to serve a special
purpose (controlling a robot), while others are more flexible general-purpose
tools that are suitable for many types of applications.
A program on the other hand can also be referred to as a series of instructions given to a computer to direct
it to carry out certain operations. Therefore a computer program is
a series of instructions that directs a computer to perform tasks. Anyone who
develops a computer by creating and modifying a computer program is called a
computer programmer. These programmers mostly create a program by coding or
writing a program’s instruction using a programming language. A programming
language is a set of words, abbreviations, and symbols that enables a
programmer to communicate instructions to a computer.
The five generational programming
languages are explained below:
1. The first-generational
language (1940-1956): this is the level of instructions and data that the
processor is actually given to work on (which in conventional computers is a
string of 0s and 1s). First generation computers relied on machine
language, the lowest-level programming language understood by computers to
perform operations and they could only solve one problem at a time. Input was
based on punched cards and paper tape, and output was displayed on printouts. The first generational language mostly used the
machine language and programmer must specify every detail of
an operation, The UNIVAC
and ENIAC computers
are examples of first-generation computing devices.
2. Second-generational
language (1956-1963):
second-generation language is sometimes called assembly language. An assembler or programmer converts the assembler
language statements into machine language and also writes instructions
using symbolic instruction codes. They are also classified as low-level
languages because detailed knowledge of hardware is still required. Assembly
languages use mnemonic operation codes and symbolic addresses in place of 1s
and 0s to represent the operation codes. A mnemonic is an alphabetical
abbreviation used as memory aid. This means a programmer can use abbreviation
instead of having to remember lengthy binary instruction codes. For example, it
is much easier to remember L for Load, A for Add, B for Branch, and C for
Compare than the binary equivalents i-e different combinations of 0s and 1s.
III. 3. Third-generational
language (1964-1971): third-generation
language is a high-level programming language such as PL/I, C programming language, COBOL (Common Business‐Oriented Language) or Java, PASCAL,
FORTRAN, BASIC, C+ and C++. It is a procedural language where the programmer writes instructions
that tell the computer what to accomplish and how to do it. Over here, compiler
translates an entire program before executing it and the interpreter convert
and execute one code statement at a time. High-level languages often are
machine independent. A machine-independent language can run on many different
types of computers and operating systems. It is noted that the two main
programming language that was used in this generation was the translator and
the compiler.
IV 4. Fourth-generation
language (1971-present): A 4GL is a non-procedural language that
enables users and programmers to access data in a database. With a
non-procedural language, the Programmer writes English-like instructions or
interacts with a graphical environment to retrieve data from files or a
database. Non-procedural languages typically are easier to use than procedural
languages. One popular 4GL is SQL. SQL is a query language that allows users to
manage, update, and retrieve data in a relational DBMS. These languages allow
database administrators to define a database, its structure and enable users to
maintain and access the data in the database. It is also a high level language.
They
are non-procedural languages, so named because they allow programmers and users
to specify what the computer is supposed to do without having to specify how
the computer is supposed to do it.
V. 5. Fifth-generation
language (Present and Beyond):
5 GL is a programming language based on solving problems using
constraints given to the program, rather than using an algorithm written by a
programmer. These are computing devices based on
artificial intelligence. The goal of
fifth-generation computing is to develop devices that respond to natural
language input and are capable of learning
and self-organization. The use of natural language touches on expert
systems, computerized collection of the knowledge of many human experts in a
given field, and artificial intelligence, independently smart computer systems.
2. WAYS TO DEVELOP WEB PAGES.
A
webpage can be defined as a document with its own address or a web document that is suitable for the World Wide Web
and the web browser. Web
developers use different kinds of techniques to create Web pages. Some
of these techniques are explained below:
HTML
(Hypertext Markup Language) is a
special formatting language that programmers use to format documents for
display on the Web. XHTML (extensible HTML) is a markup language that
includes features of HTML and XML. XML and WML are popular
formats used by Web developers. The web page authorizing software uses four
popular authorizing programs which are the Dreamweaver,
Expression Web, Flash and the SharePoint designer. A scripting language is
an interpreted language that programmers use to add dynamic content and
interactive elements to Web pages. Popular scripting languages include JavaScript,
Perl, PHP, Rexx, Tcl, and VBScript. Dynamic
HTML (DHTML) is a type of HTML that allows developers to include
more graphical interest and interactivity in a Web page.
3) STEPS IN THE PROGRAM DEVELOPMENT LIFE CYCLE.
The program development life
cycle (PDLC) consist of the various a series of steps
of programs used to build computer programs. Program development has a life
cycle. This life cycle helps the programmers to know the right way to develop a
program. This life cycle has six steps which are;
·
Analyzing requirement
·
Design solution
·
Validate design
·
Implement design
·
Test solution
·
Document solution
- Analyze requirements: analyzing requirement is the first step of the program development cycle whereby the programmer analyses the requirements of the problem the program should solve, so that the programmer can begin to develop an appropriate solution. The programmer first initiate development by reviewing the requirements, meets the system analyst and users and identifies input, processing, outputs and data components.
- Design solution: Here the programmers design the solution that will meet the users’ requirements that was gotten in the first step. The programmer designing the solution involves devising a solution algorithm to satisfy the requirement. The system can be designed using process modeling which is a structured design or object modeling which is also an object oriented design. The approach used during system development determines the techniques a programmer uses in designing a solution
- Validate design: after programmers have developed or designed their solution algorithm, they should check or validate the accuracy of the designed program. During this step, the programmer checks the logic for accuracy and attempts to uncover logic errors. A logic error is a flaw in the design that causes inaccurate results. Desk check and an inspection are the two techniques for reviewing a solution algorithm.
- Implement design: this fourth stage of implementing the design involves using a program development tool that assists the programmer by generating some or all code or includes writing the code that translates the design into a computer program. Coding a program involves translating the solution algorithm into a programming language (sometimes on paper) and then typing the programming language code into the computer.
- Test solution: once the programmer codes and enters the program the next step is to test it. The errors that are uncovered during the process are the syntax and logic errors. That main reason program is tested is to ensure that the program runs correctly with no errors.
- Document solution: Documenting solution is the last step in program design life cycle and at this stage the programmer performs two activities, the first is to review the program code where the programmer removes any dead code. A dead code is any program instructions that a program never executes. Secondly, the programmer has to review all the documentation by making sure it is complete and accurate.
4.
THE BASIC CONTROL STRUCTURES AND DESIGN TOOLS USED IN DESIGNING SOLUTIONS TO
PROGRAMMING PROBLEMS.
BRIEF
DESCRIPTION ON BASIC CONTROL STRUCTURES.
A
control structure shows the logical order of program instructions. It is also
known as a construct. The three basic control structures are sequence,
selection, and repetition. A sequence control structure shows one
or more actions following each other in order. A selection control
structure tells the program which action to take, based on
a certain condition. The two types of selection control structures are
the if-then-else control structure, which yields one of
two possibilities which is true or false and the case control structure
which can yield one of three or more possibilities. The repetition
control structure enables a program to perform one or more
actions repeatedly as long as a certain condition is met. The two forms
of the repetition control structure are: the do-while control
structure which tests a condition at the beginning of the loop
in a process called a pretest and continues looping as long as a
condition is true; and the do-until control structure which
also tests a condition at the end of the loop, in a process called a
posttet and continues looping until the condition is true.
DESIGNED
TOOLS USED IN DESIGNING SOLUTIONS TO PROGRAMMING PROBLEMS.
Design
tools help programmers to document a solution algorithm. There are two
structured designed tools and these are program flowcharts and pseudo
code. A design tool for object-oriented design is the Unified Modeling
Language (UML). The program flowcharts, pseudocode and the unified modeling
language are designed tools used in designing solutions to programming
problems. A program flowchart which can also be termed as a flowchart
graphically shows the logic in a solution algorithm whilst Pseudo code uses a
condensed form of English to convey program logic. Unified Modeling Language
(UML) on the other hand can be explained as an adopted standard notation
for object modeling and development.
Summary
by ASANTE KWAME PAAPA (SB/BMS/12/0033)
