# Integers in C

## Integers in C

Integer is written in C language as Int. Integers are whole numbers, which have no fractional part, or decimal point.

• They can be both positive and negative.
• Unsigned integers (positive values only) are supported.
• In addition, there are short and long integers.
• Examples of integers include:
• 0   57   4567   128933
• The keyword used to define integers is: int
• Integer variables are declared using:
• int variable_name;
• For example: int a;

## Long Integers

Sometimes extra digits are needed to store numbers larger than those allowed in a normal int and it is declared as long int variable_name.

The long qualifier informs C that extra storage is required for the integer. Long integers are normally in the range

-231… 231-1 or -2147483648…2147483647

## Short Integers

Sometimes less digits are needed to store a number such as

short int variable_name;

The short qualifier informs C that less storage is required for the integer and Short integers are normally in the range:

-215… 215-1 or -32768..32767

## Unsigned Integers

Unsigned integers contain positive values only

• An integer with n bits uses n bits for the number
• An integer with n bits → 2n integers in the range [0,2n-1]
•   e.g. if n=16 → 65536 integers, 0..65535
• Unsigned integers are declared:
• unsigned int variable_name;
•   unsigned short variable_name;
•   unsigned long variable_name;

## Signed Integers

Signed integers allow both positive and negative values

• An integer with n bits uses n-1 bits for the number and 1 bit for the sign
• (+ve = 0, -ve = 1)
• 2n integers in the range [-(2n-1),(2n-1-1)]
•     e.g. n=16 → 65536 integers, -322768..32767
• All int declarations default to signed
• Signed integers are declared:
• signed int variable_name;
• which is equivalent to:  int variable_name;

## A note on Integers/ints

Suffixes can be appended to an integer constant to specify its type. Can be used with int, long, or unsigned long

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