Transcript Chapter 0

Java Fondamenti di programmazione
C. Thomas Wu
© 2009 – The McGraw-Hill Companies srl
Chapter 0
Introduction to Computers
and
Programming Languages
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Animated Version
Chapter 0 - 1
Chapter 0 Objectives
• After you have read and studied this chapter, you
should be able to
– State briefly a history of computers.
– Name and describe five major components of the
computer.
– Convert binary numbers to decimal numbers and vice
versa.
– State the difference between the low-level and highlevel programming languages.
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Chapter 0 - 2
A History of Computers
• Charles Babbage is credited as the father of computer.
Although never actually built, he proposed the computing
machines called Difference Engine and Analytical Engine
that possessed the core characteristics of today’s
computers.
• Ada Lovelace, who wrote demonstration programs for
Analytical Engine, is credited as the first programmer.
• The first modern computer was built by Atanasoff of Iowa
State University in the late 1930s.
• An electromechanical computer MARK I was built by
Howard Aiken of Harvard.
• The first completely electronic computer ENIAC I was built
by Mauchly and Eckert of the University of Pennsylvania.
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Chapter 0 - 3
Computer Architecture
Output
Devices
Communication
Devices
Input
Devices
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RAM
CPU
Storage
Devices
Chapter 0 - 4
Progress of CPU Speed
For more information on Intel CPUs, click
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Intel Museum or Quick Reference Chart.
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Decimal Number Representation
decimal
point
How the decimal
number is represented.
104
103
102
101
10 1 10 2
100
103
Position Values
Example:
2
4
8
7
10 2
101
100
101
= 2  10 2 + 4  10 1+ 8  100 + 7  10 1
= 2  100 + 4  10 + 8  1
+ 7  1/10
= 200
+ 7 /10 = 248.7
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+ 40
+ 8
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Binary Number Representation
binary
point
How the binary number
is represented.
24
23
22
21
21
20
2 2
23
Position Values
1
0
1
1
22
21
20
2 1
Example:
= 1  22 + 0  21 + 1  20 + 1  2 1
= 1  4 + 0  2 + 1  1 + 1  1/2
= 4
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+0
+ 1
+ 1/2
=
5.5
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Programming Languages
• Three levels of programming languages:
– Machine Languages
– Machine language instructions are binary coded and very low level.
– Assembly Languages
– Assembly language allows symbolic programming. Requires an
assembler to translate assembly programs into machine programs.
– High-level Languages
– High-level language provides a very high conceptual model of
computing. Requires a compiler to translate high-level programs into
assembly programs.
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Chapter 0 - 8
Java
• Java is a high-level object-oriented language
developed by Sun Microsystems.
• Two types of Java programs:
• An applet runs within a web browser
• An application is a complete stand-alone program that does not
require a web browser.
• Java’s clean design and wide availability make it
an ideal language for teaching the fundamentals of
computer programming.
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