1) constant, "constant" is a quantity that will not be modified when the program runs. In other words, although constants serve hardware, software and programming languages, they are not introduced because of hardware, software and programming languages.

Constants are divided into different types, such as 25, 0 and -8 are integer constants, 6.8 and -7.89 are real constants, and' a' and' b' are character constants. Constants can usually be judged from their literal forms. This constant is called literal constant or direct constant.

2) Another meaning is that their coding methods remain unchanged. For example, whether in hardware, software or various programming languages, the information encoding of the character' a' is 0x4 1.

3) In some advanced programming languages other than C/C++, constants can be called, in a changing process, constants. It can be some time-invariant quantities and information, or it can be a character or string representing a certain value, which is often used for identification, measurement and comparison.

4) However, in C/C++ language, if constants are still used as invariants in the running process, it will be inaccurate, even in concrete use, which is a wrong concept. When defining pointer constants in C/C++, several different forms can be defined according to the position of const. Although it conforms to the concept of constant, its value or address value will change during operation.

Reference:/link? URL = fjypyn 0 e 8 idepthmzjxjbrnkk _ wlzncqinbfhbkemsoj 6 CP 4 yck _ azymewxassjb 3 wtqdn 66 xot 1 fb2 lesamwudnfitkhxzohxaxwz 3 gisbq