How to define constants in the C language?

In C language, constants can be defined in the following way:

1. Integer constants can be in decimal, octal, or hexadecimal form. For example:

int dec = 10;      // 十进制常量
int oct = 012;     // 八进制常量，等同于10
int hex = 0xA;     // 十六进制常量，等同于10

1. Floating-point constants: they can be floating-point numbers in decimal or exponential form. For example:

float f = 3.14;    // 小数形式的浮点数常量
float e = 2.7e-3;  // 指数形式的浮点数常量，等同于0.0027

1. Character constants: characters enclosed in single quotes. For example:

char c = 'a';      // 字符常量

1. String constants are sequences of characters enclosed in double quotation marks. For example:

char str[] = "Hello, world!";   // 字符串常量

1. Define

#define MAX_SIZE 100    // 符号常量

In programming, the value of constants is fixed and cannot be changed. Therefore, once constants are defined, their value will remain unchanged.