DATATYPES,KEYWORDS,FORMATSPECS

1. DATA TYPES, KEYWORDS,
INPUT/OUTPUT AND FORMAT
SPECIFIERS

2. DATA TYPES
• Data types in c refer to an extensive system used for declaring
variables or functions of different types.
• The type of a variable determines how much space it occupies in
storage and how the bit pattern stored is interpreted.

3. BASIC DATA TYPES
• The basic data types are integer-based and floating-point based. C
language supports both signed and unsigned literals.
Data Types Memory
Size
unsigned signed
char 1 byte 0 to 255 −128 to 127
short 2 byte 0 to 65,535 -32,768 to 32,767
int 2 byte 0 to 65,535 −32,768 to 32,767
float 4 byte 1.2E-38 to 3.4E+38
double 8 byte 2.3E-308 to 1.7E+308
long double 10 byte 3.4E-4932 to 1.1E+4932

4. VOID DATA TYPES
• The void type specifies that no value is available. It is used in three
kinds of situations −
• Function returns as void: A function with no return value has the
return type as void. For example, void exit (int status);
• Function arguments as void: A function with no parameter can
accept a void. For example, int rand(void);
• Pointers to void: A pointer of type void * represents the address of an
object, but not its type. For example, a memory allocation
function void *malloc( size_t size ); returns a pointer to void which
can be casted to any data type.

5. KEYWORDS
• A keyword is a reserved word. You cannot use it as a variable name,
constant name, etc. There are only 32 reserved words (keywords) in
the C language.

6. INPUT AND OUTPUT
• C language has standard libraries that allow input and output in a
program.
• The stdio.h or standard input output library in C that has methods for
input and output.
• scanf(): The scanf() method, in C, reads the value from the console as per
the type specified. Syntax:
scanf(“%X”, &variableOfXType);
• printf(): The printf() method, in C, prints the value passed as the
parameter to it, on the console screen. Syntax:
printf(“%X”, variableOfXType);

7. FORMAT SPECIFIERS
• The format specifiers are used in
C for input and output purposes.
• Using this concept the compiler
can understand that what type of
data is in a variable during taking
input using the scanf() function
and printing using printf()
function.
Format Specifier Type
%c Character
%d Signed integer
%f Float values
%l or %ld or %li Long
%lf Double
%s String
%p Pointer