1.Integer is an integer, such as 5,8, which is different from decimal (called floating point number in computer). For example, 5.8 is a decimal, not an integer variable, which means that it can be changed, such as int I；; I is a variable, you can assign it i=2, i=3 and so on. It is different from a constant, such as 5. It is a constant and cannot be assigned, such as 5 = 6, which is unacceptable. An integer variable is a variable that can be assigned an integer value.

Second, integer variables

Integer variables can be divided into the following categories:

1. basic type

The type specifier is int, which occupies 2 bytes in memory and its value is a basic integer constant.

2. Short integers

The type specifier is short int or short' c110f1. The range of bytes and values occupied is the same as that of the basic type.

3. Long integers

The type specifier is long int or long, occupying 4 bytes of memory, and its value is long integer constant.

4. Unsigned types

The type specifier is unsigned.

Unsigned types can match the above three types:

(1) The unsigned primitive type specifier is unsigned int or unsigned.

(2) The unsigned short integer type specifier is an unsigned short integer.

(3) The unsigned long integer specifier is an unsigned long integer.