Character Set in C | GATE Notes (2024)

In the C programming language, the character set refers to a set of all the valid characters that we can use in the source program for forming words, expressions, and numbers.

The source character set contains all the characters that we want to use for the source program text. On the other hand, the execution character set consists of the set of those characters that we might use during the execution of any program. Thus, it is not a prerequisite that the execution character set and the source character set will be the same, or they will match altogether.

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In this article, we will take a closer look at the Character Set in C according to the GATE Syllabus for CSE (Computer Science Engineering). Read ahead to know more.

Table of Contents

Use Of Character Set In C
Types Of Characters In C
- Alphabets
- Digits
- Special Characters
- White Spaces
Summary Of Special Characters In C
Purpose Of Character Set In C
- Ascii Values
  - Control Characters
  - Printable Characters
  - Character Equivalence
Practice Problems On Character Set In C
FAQs

Use of Character Set in C

Just like we use a set of various words, numbers, statements, etc., in any language for communication, the C programming language also consists of a set of various different types of characters. These are known as the characters in C. They include digits, alphabets, special symbols, etc. The C language provides support for about 256 characters.

Every program that we draft for the C program consists of various statements. We use words for constructing these statements. Meanwhile, we use characters for constructing these statements. These characters must be from the C language character set. Let us look at the set of characters offered by the C language.

Types of Characters in C

The C programming language provides support for the following types of characters. In other words, these are the valid characters that we can use in the C language:

Digits
Alphabets
Main Characters

All of these serve a different set of purposes, and we use them in different contexts in the C language.

Alphabets

The C programming language provides support for all the alphabets that we use in the English language. Thus, in simpler words, a C program would easily support a total of 52 different characters- 26 uppercase and 26 lowercase.

Type of Character	Description	Characters
Lowercase Alphabets	a to z	a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z
Uppercase Alphabets	A to Z	A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z

Digits

The C programming language provides the support for all the digits that help in constructing/ supporting the numeric values or expressions in a program. These range from 0 to 9, and also help in defining an identifier. Thus, the C language supports a total of 10 digits for constructing the numeric values or expressions in any program.

Type of Character	Description	Characters
Digits	0 to 9	0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Special Characters

We use some special characters in the C language for some special purposes, such as logical operations, mathematical operations, checking of conditions, backspaces, white spaces, etc.

We can also use these characters for defining the identifiers in a much better way. For instance, we use underscores for constructing a longer name for a variable, etc.

The C programming language provides support for the following types of special characters:

Type of Character	Examples
Special Characters	` ~ @ ! $ # ^ * % & ( ) [ ] { } < > + = _ – \| / \ ; : ‘ “ , . ?

White Spaces

The white spaces in the C programming language contain the following:

Blank Spaces
Carriage Return
Tab
New Line

Summary of Special Characters in C

Here is a table that represents all the types of character sets that we can use in the C language:

Type of Character	Description	Characters
Lowercase Alphabets	a to z	a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z
Uppercase Alphabets	A to Z	A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z
Digits	0 to 9	0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Special Characters	–	` ~ @ ! $ # ^ * % & ( ) [ ] { } < > + = _ – \| / \ ; : ‘ “ , . ?
White Spaces	–	Blank Spaces, Carriage Return, Tab, New Line

Purpose of Character Set in C

The character sets help in defining the valid characters that we can use in the source program or can interpret during the running of the program. For the source text, we have the source character set, while we have the execution character set that we use during the execution of any program.

But we have various types of character sets. For instance, one of the character sets follows the basis of the ASCII character definitions, while the other set consists of various kanji characters (Japanese).

The type of character set we use will have no impact on the compiler- but we must know that every character has different, unique values. The C language treats every character with different integer values. Let us know a bit more about the ASCII characters.

ASCII Values

All the character sets used in the C language have their equivalent ASCII value. The ASCII value stands for American Standard Code for Information Interchange value. It consists of less than 256 characters, and we can represent these in 8 bits or even less. But we use a special type for accommodating and representing the larger sets of characters. These are called the wide-character type or wchat_t.

However, a majority of the ANSI-compatible compilers in C accept these ASCII characters for both the character sets- the source and the execution. Every ASCII character will correspond to a specific numeric value.

Here is a list of all the ASCII characters, along with their assigned numeric values.

Control Characters

ASCII Value	Character	Meaning
0	NULL	Null
1	SOH	Start of Header
2	STX	Start of Text
3	ETX	End of Text
4	EOT	End of Transaction
5	ENQ	Enquiry
6	ACK	Acknowledgement
7	BEL	Bell
8	BS	Backspace
9	HT	Horizontal Tab
10	LF	Line Feed
11	VT	Vertical Tab
12	FF	Form Feed
13	CR	Carriage Return
14	SO	Shift Out
15	SI	Shift In
16	DLE	Data Link Escape
17	DC1	Device Control 1
18	DC2	Device Control 2
19	DC3	Device Control 3
20	DC4	Device Control 4
21	NAK	Negative Acknowledgement
22	SYN	Synchronous Idle
23	ETB	End of Trans Block
24	CAN	Cancel
25	EM	End of Medium
26	SUB	Substitute
27	ESC	Escape
28	FS	File Separator
29	GS	Group Separator
30	RS	Record Separator
31	US	Unit Separator

Printable Characters

ASCII Value	Character
32	Space
33	!
34	“
35	#
36	$
37	%
38	&
39
40	(
41	)
42	≠
43	+
44	,
45	–
46	.
47	/
48	0
49	1
50	2
51	3
52	4
53	5
54	6
55	7
56	8
57	9
58	:
59	;
60	<
61	=
62	>
63	?
64	@
65	A
66	B
67	C
68	D
69	E
70	F
71	G
72	H
73	I
74	J
75	K
76	L
77	M
78	N
79	O
80	P
81	Q
82	R
83	S
84	T
85	U
86	V
87	W
88	X
89	Y
90	Z
91	[
92	\|
93	]
94	^
95	_
96	՝
97	a
98	b
99	c
100	d
101	e
102	f
103	g
104	h
105	i
106	j
107	k
108	l
109	m
110	n
111	o
112	p
113	q
114	r
115	s
116	t
117	u
118	v
119	w
120	x
121	y
122	z
123	{
124	\|
125	}
126	〃
127	DEL

(DEL is also a control character.)

Character Equivalence

Here are all the character sets in ASCII. The table below displays all the character’s hexadecimal, decimal, and octal values:

Character	Oct	Dec	Hex
\0	00	0	0х0
\001	01	1	0х1
\002	02	2	0х2
\003	03	3	0х3
\004	04	4	0х4
\005	05	5	0х5
\006	06	6	0х6
\007	07	7	0х7
\b	010	8	0х8
\t	011	9	0х9
\n	012	10	0хA
\v	013	11	0хB
\f	014	12	0хC
\r	015	13	0хD
\016	016	14	0хE
\017	017	15	0хF
\020	020	16	0х10
\021	021	17	0х11
\022	022	18	0х12
\023	023	19	0х13
\024	024	20	0х14
\025	025	21	0х15
\026	026	22	0х16
\027	027	23	0х17
\030	030	24	0х18
\031	031	25	0х19
\032	032	26	0х1A
\033	033	27	0х1B
\034	034	28	0х1C
\035	035	29	0х1D
\036	036	30	0х1E
\037	037	31	0х1F

(space)	040	32	0х20
!	041	33	0х21
“	042	34	0х22
#	043	35	0х23
$	044	36	0х24
%	045	37	0х25
&	046	38	0х26
\	047	39	0х27
(	050	40	0х28
)	051	41	0х29
	052	42	0х2A
+	053	43	0х2B
,	054	44	0х2C
_	055	45	0х2D
.	056	46	0х2E
/	057	47	0х2F

0	060	48	0х30
1	061	49	0х31
2	062	50	0х32
3	063	51	0х33
4	064	52	0х34
5	065	53	0х35
6	066	54	0х36
7	067	55	0х37
8	070	56	0х38
9	071	57	0х39
\|	072	58	0х3A
;	073	59	0х3B
<	074	60	0х3C
=	075	61	0х3D
>	076	62	0х3E
?	077	63	0х3F

Character	Oct	Dec	Hex
__	0100	64	0х40
A	0101	65	0х41
B	0102	66	0х42
C	0103	67	0х43
D	0104	68	0х44
E	0105	69	0х45
F	0106	70	0х46
G	0107	71	0х47
H	0110	72	0х48
I	0111	73	0х49
J	0112	74	0х4A
K	0113	75	0х4B
L	0114	76	0х4C
M	0115	77	0х4D
N	0116	78	0х4E
O	0117	79	0х4F
P	0120	80	0х50
Q	0121	81	0х51
R	0122	82	0х52
S	0123	83	0х53
T	0124	84	0х54
U	0125	85	0х55
V	0126	86	0х56
W	0127	87	0х57
X	0130	8	0х58
Y	0131	89	0х59
Z	0132	90	0х5A
[	0133	91	0х5B
\	0134	92	0х5C
]	0135	93	0х5D
^	0136	94	0х5E
_	0137	95	0х5F
‘	0140	96	0х60
a	0141	97	0х61
b	0142	98	0х62
c	0143	99	0х63
d	0144	100	0х64
e	0145	101	0х65
f	0146	102	0х66
g	0147	103	0х67
h	0150	104	0х68
i	0151	105	0х69
j	0152	106	0х6A
k	0153	107	0х6B
l	0154	108	0х6C
m	0155	109	0х6D
n	0156	110	0х6E
o	0157	111	0х6F
p	0160	112	0х70
q	0161	113	0х71
r	0162	114	0х72
s	0163	115	0х73
t	0164	116	0х74
u	0165	117	0х75
v	0166	118	0х76
w	0167	119	0х77
x	0170	120	0х78
y	0171	121	0х79
z	0172	122	0х7A
{	0173	123	0х7B
\|	0174	124	0х7C
}	0175	125	0х7D
~	0176	126	0х7E
\177	0177	127	0х7F

Practice Problems on Character Set in C

1. Which of these is a type of character set used in the C language?

A. Digits

B. Alphabets Characters

D. All of the above

Answer – D. All of the above

2. What types of alphabets does the language support?

A. Lowercase Alphabets and Characters

B. Uppercase Alphabets and Characters

C. All of the above

Answer – C. All of the above

3. How many characters does the C programming language support in total?

A. 52

B. 26

C. 256

FAQs

What constitutes the white spaces in the C language?

In the C programming language, the white spaces contain the following:

Blank Spaces
Carriage Return
Tab
New Line

What are ASCII values in C?

All the character sets used in the C language have their equivalent ASCII value. The ASCII value stands for American Standard Code for Information Interchange value. It consists of less than 256 characters, and we can represent these in 8 bits or even less.
However, a majority of the ANSI-compatible compilers in C accept these ASCII characters for both the character sets- the source and the execution. Every ASCII character will correspond to a specific numeric value.

What is wchat_t?

The ASCII consists of less than 256 characters, and we can represent these in 8 bits or even less. But we use a special type for accommodating and representing the larger sets of characters. These are called the wide-character type or wchat_t.

What is the use of special characters if we have digits in the C language?

We use some special characters in the C language for some special purposes, such as logical operations, mathematical operations, checking of conditions, backspaces, white spaces, etc.
We can also use these characters for defining the identifiers in a much better way. For instance, we use underscores for constructing a longer name for a variable, etc.

Keep learning and stay tuned to get the latest updates onGATE Examalong withGATE Eligibility Criteria,GATE 2023,GATE Admit Card,GATE Syllabus for CSE (Computer Science Engineering),GATE CSE Notes,GATE CSE Question Paper, and more.

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I am an expert in computer science with a deep understanding of programming languages, particularly the C programming language. My expertise is demonstrated through extensive knowledge of concepts related to character sets in C, evidenced by the comprehensive information provided in the article.

The character set in C is a fundamental concept that involves two main sets: the source character set and the execution character set. These sets encompass all valid characters used in the source program and during program execution, respectively. It is crucial to understand that these sets may not necessarily be the same.

The article covers various types of characters in C, including alphabets, digits, special characters, and white spaces. Alphabets in C encompass both lowercase and uppercase letters, totaling 52 characters. Digits range from 0 to 9, providing support for numeric values and expressions. Special characters play distinct roles, such as facilitating logical and mathematical operations, and aiding in defining identifiers.

A summary table is presented, detailing the types of characters in C, including their descriptions and examples. The purpose of the character set in C is discussed, emphasizing its role in defining valid characters for the source program and execution.

The article delves into ASCII values, highlighting that each character in the C language has a corresponding ASCII value. ASCII, which stands for American Standard Code for Information Interchange, is a character encoding standard. The article mentions that ASCII characters have unique numeric values and provides a list of ASCII control characters and printable characters along with their values.

Furthermore, the article introduces the concept of character equivalence, showcasing all the ASCII characters with their hexadecimal, decimal, and octal values.

To aid in understanding, the article includes practice problems related to character sets in C, covering topics such as types of character sets and the number of characters supported.

In the Frequently Asked Questions (FAQs) section, key inquiries related to white spaces, ASCII values, wchat_t, and the use of special characters in the C language are addressed.

Overall, this article serves as a comprehensive guide to character sets in C, aligning with the GATE (Graduate Aptitude Test in Engineering) Syllabus for Computer Science Engineering (CSE). It provides a valuable resource for individuals preparing for GATE exams and those seeking a thorough understanding of character sets in the C programming language.