Integer constants are divided into decimal integer constants, octal integer constants and hexadecimal integer constants.

An expression.

(1) decimal integer constant

This constant can only have numbers from 0 to 9, and can have positive and negative signs. For example:

0 1 364 28 -34

(2) Octal integer constant

The constant is an octal numeric string starting with the number 0. Where the numbers are 0 ~ 7. For example:

0 1 1 1 (decimal 73) 0 1 1 (decimal 9) 0 123 (decimal 83)

(3) Hexadecimal integer constant

This constant is a string of hexadecimal digits starting with 0X or 0x. Where each number can be 0 ~ 9, a ~ f or a ~

Numbers or English letters in F. For example:

0x 1 1 (decimal 17) 0Xa5 (decimal 165) 0x5a (decimal 90)