ENGR/CS 101 CS Session
Lecture 1
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Course and session webpages
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http://csserver.evansville.edu/~hwang/f11-courses/engrcs101.html
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http://csserver.evansville.edu/~hwang/f11-courses/engrcs101/cs.html
Introduction sheet, turn in at the end of class.
Lecture 1
ENGR/CS 101 Computer Science Session
1
Outline
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Bits to Brains
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Binary digits (bits)
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Binary numbers
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ASCII encoding
Lecture 1
ENGR/CS 101 Computer Science Session
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Binary Digits (Bits)
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A bit is a digit that can have value 0 or 1.
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A byte is (a sequence of) 8 bits
8 bits
10011101
1 byte
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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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What is the pattern of dots on the cards?
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How many dots would the fifth card have?
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Lecture 1
What is the highest number of dots that we can
count to with these cards?
What is the smallest number of dots we can
represent with these cards?
ENGR/CS 101 Computer Science Session
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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 with the cards in this
arrangement by showing the correct number of dots
What is the pattern of flipping over the cards as you
count?
ENGR/CS 101 Computer Science Session
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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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Alphabet-based
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Ordering based on English alphabet
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Extended for other language's alphabet symbols
Lecture 1
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ASCII Encoding
Lecture 1
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
sp
32
.
46
,
44
!
33
ENGR/CS 101 Computer Science Session
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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?
Lecture 1
ENGR/CS 101 Computer Science Session
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In-class Exercise
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Decode the ASCII message on the worksheet
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Write the name of your hometown in ASCII
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Turn in the worksheet before you leave.
Lecture 1
ENGR/CS 101 Computer Science Session
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