ENGR/CS 101 CS Session
Lecture 1
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Course and session webpages
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http://csserver.evansville.edu/~hwang/f12-courses/engrcs101.html
http://csserver.evansville.edu/~hwang/f12-courses/engrcs101/cs.html
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Introduction sheet, turn in at the end of class.
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(Pre)Registration session for spring classes
will be on Monday, October 29. CS in KC267, CoE in KC-137, EE in KC-136.
Lecture 1
ENGR/CS 101 Computer Science Session
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Outline
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What is Computer Science?
Bits to Brains
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Lecture 1
Binary digits (bits)
Binary numbers
ASCII encoding
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What is Computer Science?
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Short video (http://www.cs.washington.edu/WhyCSE)
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"Power to Change the World"
Study of how computer programs are written
to solve problems using computation
Use an engineering approach to design and
implement a computer program
But first, a look at a basic idea underlying
computing
Lecture 1
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Binary Digits (Bits)
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A bit is a digit that can have value 0 or 1.
8 bits
10011101
1 byte
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A byte is (a sequence of) 8 bits
A word is 16, 32, or 64 bits, depending on the
machine architecture.
Lecture 1
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Binary Numbers
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Use the cards to help answer the following
questions:
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Lecture 1
What cards can we use to show 3 dots? 6 dots?
11 dots?
What is the highest number of dots that we can
represent with these cards?
What is the smallest number of dots we can
represent with these cards?
What is the pattern of the dots? How many dots
would there be on a fifth card?
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Binary Numbers
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Arrange the cards like so:
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Lecture 1
Count from 0 to 15 dots by flipping over the cards
What is the pattern as you count?
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Binary Numbers
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Each digit place represents a power of the
base of the number in decimal. E.g.,
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35610 = 3 x 102 + 5 x 101 + 6 x 100
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100111012 = 1 x 27 + 0 x 26 + 0 x 25 + 1 x 24 +
1 x 23 + 1 x 22 + 0 x 21 + 1 x 20 = 15710
What is 10001112 in decimal? What is 9710
in binary?
Lecture 1
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Characters
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Computers "speak" bits and bytes, but
humans communicate using letters, words,
and sentences.
Need to encode characters into bits. One
such encoding is called ASCII (American
Standard Code for Information Interchange).
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Lecture 1
Alphabet-based
Ordering based on English alphabet
Extended for other language's alphabet symbols
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ASCII Encoding (Decimal)
A
65
N
78
a
97
n
110
B
66
O
79
b
98
o
111
C
67
P
80
c
99
p
112
D
68
Q
81
d
100
q
113
E
69
R
82
e
101
r
114
F
70
S
83
f
102
s
115
G
71
T
84
g
103
t
116
H
72
U
85
h
104
u
117
I
73
V
86
I
105
v
118
J
74
W
87
j
106
w
119
K
75
X
88
k
107
x
120
L
76
Y
89
l
108
y
121
M
77
Z
90
m
109
z
122
space
32
!
33
,
44
.
46
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Characters
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How many bits will it take to implement ASCII
encoding of characters?
Can you find a mathematical equation to
calculate the number of bits needed to
represent a number n?
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In-class Exercise
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Decode the ASCII message on the worksheet
Write your first name in ASCII in binary
Turn in the worksheet and the introduction
sheet before you leave.
Lecture 1
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