Software is a collection of
programs and program is a collection of instructions given to the computer. Development
is a stepwise process, before developing a software number of processes are
done. The first step is to understand the user requirements. Problem analysis
arises during the requirement phase of software development. Problem analysis
is done for obtaining the user requirements and to determine the input and
output of a program. For solving any problem, an algorithm is implemented.
Process of Program Development
1. Programming Languages:
1. Programming Languages:
Before Learning any language, it
is important to know about the various types of languages and their features.
The Languages are classified into two types.
1. Low
level Languages
2. High
level Languages
1.1. Low level Languages:
The Languages in this
category are the Machine level and Assembly level languages.
1.1.1 Machine
level Language:
Computers can understand only digital signals, which are in binary
digits i.e., 0 and 1. So the instructions given to the computer can only in
binary codes. The machine language consists of instructions that are in binary
0 or 1. Computers can understand only Machine level Language.
Writing a program in machine level language is a difficult task because
it is not easy for programmers to write instructions in binary code. A machine
level Language program is error-prone and its maintenance is very difficult.
Every computer has its own Machine Instructions, so the programs written for
one computer are not valid for other computers.
1.1.2 Assembly
Language
The difficulties faced in
machine level language were reduced to some extent by using a modified form of
Machine level language called assembly language. A computer can understand only
machine level language, assembly language program must be translated into
machine language. The translator that is used for translating is called
“assembler”.
In this Language data
stored in Computer registers and each computer has different set of registers.
The assembly Language is not portable. Since the low level Languages are
related with the hardware, the execution of a low-level program is faster.
1.2 High
level Language :
High -level Languages are
designed keeping in mind the features of portability i.e., these languages are
Machine independent. While programming in a high level language, the programmer
is not concerned with the low level details, and so the whole attention can be
paid to the logic of the problem being solved. For translating high-level
languages into machine language, compiler or interpreter is used. Every
Language has its own Compiler or interpreter.
2. Translators :
Translators are just a computer programs, which accept a program written
in high level or low level language and produce an equivalent machine language
program as output. Three types of translators used are
a. Assembler
b. Compiler
c. Interpreter
Assembler is used for converting the code of low
level language (assembly language) into Machine Language.
Compilers and interpreters are used to convert the
code of high-level language into Machine language. The High level program is
known as source program and corresponding machine language is known as object
program.
Compiler Searches all the errors of the program and
lists them. If the program is error free then it converts the code of program
into machine code and then the program can be executed by separate commands. An
interpreter Checks the errors of program statement by statement. After checking
one statement, it converts that statement into machine code and then executes
that statement. This process continues until the last statement of program or
erroneous statement occurs.