CSIT111 Lecture 2.pptx - CSIT111 Programming Fundamentals...

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CSIT111 Programming Fundamentals
Object Oriented Programming
Concept
面向对象编程概念

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Focus of this subject
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This subject is not only about Java
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If you know a programming language and you know how
to use computers, it does not mean that you can develop
software systems
If you know alphabet and you
can type quickly, this may not
be enough to write a novel
To become a programmer
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you need to be familiar with advanced software
development concepts
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you need to know how to efficiently utilize these
concepts using appropriate programming languages

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Software development challenge
Software development has unique challenges which are
not common for other industries
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When you design a car you can foresee how it will look like when it is made
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Reverse engineering can reproduce car design documents (
identical to original
ones
)
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When a program is executed, it is
a sequence of invisible electrical
signals which represent binary
microprocessor instructions
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It is practically impossible to
reproduce the original program
code from binary instructions
How to design
programs
when you can't
see the final
product?
However…

Imperative Programming Concept
The oldest concept where a program consists of a
sequence of commands for the microprocessor to execute
Example: Assembly language is a symbolic representation
of microprocessor instructions with one-to-one mapping
pushl %ebp 11010011
movl %esp, %ebp 01010010
addl 8(%ebp), %eax 10000011
How to increase
productivity of software
development?
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When you virtually have to 'live in the microprocessor' and think like a
machine to write even a simple program, you cannot be productive
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It is close to impossible to reuse assembly code. You need to start every
new project practically from scratch
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How to find an efficient design methodology ?
Can software be built
from pre-designed
pre-tested parts too?