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CS session webpage http://csserver.evansville.edu/~hwang/f13-courses/cs101.html
 Introduction sheet, turn in at the end of class
 The CS session constitutes 1/3 of the final course grade for ENGR/CS 101
Lecture 1 ENGR/CS 101 Computer Science Session 1

 What is Computer Science?
 Bits to Brains
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Binary digits (bits)
Binary numbers
ASCII encoding
Lecture 1 ENGR/CS 101 Computer Science Session 2

 Short video by University of Washington
 "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 ENGR/CS 101 Computer Science Session 3

 A bit is a digit that can have value 0 or 1.
8 bits
10011101
1 byte
 A byte is (a sequence of) 8 bits
 A word is 16, 32, or 64 bits, depending on the machine architecture.
Lecture 1 ENGR/CS 101 Computer Science Session 4

 Use the cards to help answer the following questions:
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
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?
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Lecture 1
What is the pattern of the dots? How many dots would there be on a fifth card?
ENGR/CS 101 Computer Science Session 5

 Arrange the cards like so:
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Count from 0 to 15 dots by flipping over the cards
What is the pattern as you count?
Lecture 1 ENGR/CS 101 Computer Science Session 6

 Each digit place represents a power of the base of the number in decimal. E.g.,
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356
10
= 3 x 10 2 + 5 x 10 1 + 6 x 10 0
10011101
2
= 1 x 2 7 + 0 x 2 6 + 0 x 2 5 + 1 x 2 4 +
1 x 2 3 + 1 x 2 2 + 0 x 2 1 + 1 x 2 0 = 157
10
 What is 1000111
2
in decimal? What is 97
10 in binary?
Lecture 1 ENGR/CS 101 Computer Science Session 7

 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
Ordering based on English alphabet
Extended for other languages' alphabet symbols
Lecture 1 ENGR/CS 101 Computer Science Session 8

69
70
71
72
65
66
67
68
73
74
75
76
77
E
F
G
H
A
B
C
D
I
J
K
L
M
82
83
84
85
78
79
80
81
86
87
88
89
90
R
S
T
U
N
O
P
Q
V
W
X
Y
Z
97
98
99
100
101
102
103
104
105
106
107
108
109 e f g h a b c d k l
I j m r s t u n o p q v w x y z
110
111
112
113
114
115
116
117
118
119
120
121
122 space
Lecture 1
32 ! 33 , 44
ENGR/CS 101 Computer Science Session
. 46
9

 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 10

 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 ENGR/CS 101 Computer Science Session 11