Constants and variables

1. Constants

(1) Integral type constant

100,23,33 and so on;

(2) Real-type constants

2.1,34.7, etc.

(3) Character constants

Ordinary characters such as ' A ', ' a ', and escape characters

(4) String constants

"ABC", "342" and so on

(5) Symbolic constants

#define PI 3.141592

2. Variables

int a,b,c;

3, constant variable (C 99 allows the use of constant variables)

const int a=3; Indicates that a is defined as an integer variable, specifying its value to be 3, and its value cannot be changed during the existence of a variable.

4. Identifiers

Constants and variables