Introduction

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When Using This Book  ‣ How To Do Well In This Course  ‣ Practice Glossary

Practice Problem Answers (OLD)

Chapter 1 : Number Bases 1.1 : Base-10 1.2 : Base-2 1.3 : Base-16 1.4 : HTML Colors

Chapter 2 : More on Binary 2.1 : Negative Numbers 2.2 : Fractional Binary 2.3 : Addition and Subtration

Chapter 3 : Character Sets 3.1 : ASCII 3.2 : Unicode

Chapter 4 : Boolean Algebra 4.1 : An Overview 4.2 : Basic Operators 4.2.1 : Not 4.2.2 : Or 4.2.3 : And 4.2.4 : Nor 4.2.5 : Nand 4.2.6 : Xor 4.3 : Complex Expressions 4.4 : Half Adder 4.5 : Full Adder 4.6 : Arithmetic Logic Unit 4.7 : Digital Logic Workbench 4.8 : Minecraft

Chapter 5 : The CARDIAC 5.1 : The Hardware 5.2 : Programming the CARDIAC 5.3 : Assembly and Machine Language

Chapter 6 : Languages 6.1 : Processing Language 6.2 : Markup Languages 6.3 : Programming Languages 6.4 : Tranquility 6.4.1 : TRANQC (1) 6.4.2 : ALLOC (3) 6.4.3 : BUTTON (3) 6.4.4 : HTML (3) 6.4.5 : I2S (3) 6.4.6 : IMG (3) 6.4.7 : LABEL(3) 6.4.8 : PRINT (3) 6.4.9 : RANDOM (3) 6.4.10 : READ (3) 6.4.11 : TABLE (3) 6.4.12 : TIMER (3) 6.5 : State and State Machines

Chapter 8 : Graphics 8.1 : Bresenham's

Chapter 10 : Cryptography 10.1 : RSA Math Background 10.2 : RSA Key Generation 10.3 : RSA Encryption

Warning: Update in progress. Before adding new content, I'm going through and updating the content that already existed that I haven't touched in years. Also fixing up a lot of CSS. I wrote bad code a very long time ago and it's taking a while to update it.
This page has not been looked at yet My apologies for any issues this may cause.

3.1 : ASCII

While there are many different character sets, the one we're gonna focus on is ASCII. ASCII stands for the American Standard Code for Information Interchange. It's a character set which means it was created for computers to display information. As we know, computers can only store 0s and 1s. However, what if we want to display the text "Hello"? We cannot store the letters themselves in the computers code. ASCII is a 7 bit binary code for each letter. Typically the 7 bits are separated into a set of 3 and 4 with a space. This is only for readability purposes. These 7 bits allows strings of text to be stored within the computer to be displayed later. ASCII has 128 characters in the table. I have been very generous and listed them all below.

	Binary	Decimal	Character	Binary	Decimal	Character	Binary	Decimal	Character	Binary	Decimal	Character
	000 0000	0	NUL (null)	010 0000	32	Space	100 0000	64	@	110 0000	96	`
	000 0001	1	SOH (start of heading)	010 0001	33	!	100 0001	65	A	110 0001	97	a
	000 0010	2	STX (start of text)	010 0010	34	"	100 0010	66	B	110 0010	98	b
	000 0011	3	ETX (end of text)	010 0011	35	#	100 0011	67	C	1100001	99	c
	000 0100	4	EOT (end of transmission)	010 0100	36	$	100 0100	68	D	110 0100	100	d
	000 0101	5	ENQ (enquiry)	010 0101	37	%	100 0101	69	E	110 0101	101	e
	000 0110	6	ACK (acknowledge)	010 0110	38	&	100 0110	70	F	110 0110	102	f
	000 0111	7	BEL (bell)	010 0111	39	'	100 0111	71	G	110 0111	103	g
	000 1000	8	BS (backspace)	010 1000	40	(	100 1000	72	H	110 1000	104	h
	000 1001	9	TAB (horizontal tab)	010 1001	41	)	100 1001	73	I	110 1001	105	i
	000 1010	10	LF (new line)	010 1010	42	*	100 1010	74	J	110 1010	106	j
	000 1011	11	VT (vertical tab)	010 1011	43	+	100 1011	75	K	110 1011	107	k
	000 1100	12	FF (new page)	010 1100	44	,	100 1100	76	L	110 1100	108	l
	000 1101	13	CR (carriage return)	010 1101	45	-	100 1101	77	M	110 1101	109	m
	000 1110	14	SO (shift out)	010 1110	46	.	100 1110	78	N	110 1110	110	n
	000 1111	15	SI (shift in)	010 1111	47	/	100 1111	79	O	110 1111	111	0
	001 0000	16	DLE (data link escape)	011 0000	48	0	101 0000	80	P	111 0000	112	p
	001 0001	17	DC1 (device control 1)	011 0001	49	1	101 0001	81	Q	111 0001	113	q
	001 0010	18	DC2 (device control 2)	011 0010	50	2	101 0010	82	R	111 0010	114	r
	001 0011	19	DC3 (device control 3)	011 0011	51	3	101 0011	83	S	111 0011	115	s
	001 0100	20	DC4 (device control 4)	011 0100	52	4	101 0100	84	T	111 0100	116	t
	001 0101	21	NAK (negative acknowledge)	011 0101	53	5	101 0101	85	U	111 0101	117	u
	001 0110	22	SYN (synchronous idle)	011 0110	54	6	101 0110	86	V	111 0110	118	v
	001 0111	23	ETB (end of trans. block)	011 0111	55	7	101 0111	87	W	111 0111	119	w
	001 1000	24	CAN (cancel)	011 1000	56	8	101 1000	88	X	111 1000	120	x
	001 1001	25	EM (end of medium)	011 1001	57	9	101 1001	89	Y	111 1001	121	y
	001 1010	26	SUB (substitute)	011 1010	58	:	101 1010	90	Z	111 1010	122	z
	001 1011	27	ESC (escape)	011 1011	59	;	101 1011	91	[	111 1011	123	{
	001 1100	28	FS (file separator)	011 1100	60	<	101 1100	92	\	111 1100	124	|
	001 1101	29	GS (group separator)	011 1101	61	=	101 1101	93	]	111 1101	125	}
	001 1110	30	RS (record separator)	011 1110	62	>	101 1110	94		111 1110	126
	001 1111	31	US (unit separator)	011 1111	63	?	101 1111	95	_	111 1111	127	DEL

Displaying Information

So now that we know how to represent each character, let's use this in practice. Let's say we want to display the string, "I'm Charlie". I chose this phrase because it has lowercase letters, capital letters, punctuation, spaces, and I am, in fact, Charlie.

Choose Phrase: I'm Charlie

Relate Letters to Binary: I = 1001001 ' = 0100111 m = 1101101 etc.

Put it Together: 1001001 0100111 1101101 0100000 1000011 1101000 1100001 1110010 1101100 1101001 1100101

Remove Spaces: 10010010100111110110101000001000011110100011000011110010110110011010011100101


As you can see the process is very simple. Translate the characters into numbers using the chart, then concatenate. While using binary is most common, you can also use the base-10 numbers. I chose binary because that's what computers read. You should try this on your own with your own phrases.

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