\b
Backspace
\f
Form feed
\n
Newline
\r
Return
\t
Horizontal tab
\v
Vertical tab
\\
Backslash
\'
Single quotation mark
\"
Double quotation mark
\?
Question mark
\0
Null character
String constants
String constants are the constants which are enclosed in a pair of double-quote marks. For example:
"good" //string constant
"" //null string constant
" " //string constant of six white space
"x" //string constant having single character.
"Earth is round\n" //prints string with newline
Enumeration constants
Keyword enum is used to declare enumeration types. For example:
enum color {yellow, green, black, white};
Here, the variable name is color and yellow, green, black and white are the enumeration constants having value 0, 1, 2 and 3
respectively by default.
C Programming Data Types
In C, variable(data) should be declared before it can be used in program. Data types are the keywords, which are used for assigning a type to a variable.
Data types in C
1. Fundamental Data Types
Integer types
Floating Type
Character types
2. Derived Data Types
Arrays
Pointers
Structures
Enumeration
Syntax for declaration of a variable
data_type variable_name;
Integer data types
Keyword int is used for declaring the variable with integer type. For example:
int var1;
Here, var1 is a variable of type integer.
The size of int is either 2 bytes(In older PC's) or 4 bytes. If you consider an integer having size of 4 byte( equal to 32 bits), it can take 232 distinct states as: -231,-231+1, ...,-2, -1, 0, 1, 2, ..., 231-2, 231-1
Similarly, int of 2 bytes, it can take 216 distinct states from -215 to 215-1. If you try to store larger number than 231-1, i.e,+2147483647
and smaller number than -231, i.e, -2147483648, program will not run correctly.
Floating types
Variables of floating types can hold real values(numbers) such as: 2.34, -9.382 etc. Keywords either float or double is used for declaring floating type variable. For example:
float var2;
double var3;
Here, both var2 and var3 are floating type variables.
In C, floating values can be represented in exponential form as well. For example:
float var3=22.442e2
Difference between float and double
Generally the size of float(Single precision float data type) is 4 bytes and that of double(Double precision float data type) is 8 bytes.
Floating point variables has a precision of 6 digits whereas the the precision of double is 14 digits.
Note: Precision describes the number of significant decimal places that a floating values carries.
Character types
Keyword char is used for declaring the variable of character type. For example:
char var4='h';
Here, var4 is a variable of type character which is storing a character 'h'.
The size of char is 1 byte. The character data type consists of ASCII characters. Each character is given a specific value. For example: For, 'a', value =97
For, 'b', value=98
For, 'A', value=65
For, '&', value=33
For, '2', value=49
Qualifiers
Qualifiers alters the meaning of base data types to yield a new data type.
Size qualifiers:
Size qualifiers alters the size of basic data type. The keywords long and short are two size qualifiers. For example:
long int i;
The size of int is either 2 bytes or 4 bytes but, when long keyword is used, that variable will be either 4 bytes of 8 bytes. Learn more about long keyword in C programming. If the larger size of variable is not needed then, short keyword can be used in similar manner as long keyword.
Sign qualifiers:
Whether a variable can hold only positive value or both values is specified by sign qualifiers. Keywords signed and unsigned are used for sign qualifiers.
unsigned int a;
// unsigned variable can hold zero and positive values only
It is not necessary to define variable using keyword signed because, a variable is signed by default. Sign qualifiers can be applied to only int and char data types. For a int variable of size 4 bytes it can hold data from -231 to 231-1 but, if that variable is defined unsigned, it can hold data from 0 to 232 -1.