A constant is a quantity whose value cannot be changed during the running of a program. Constants are divided into direct constants and symbolic constants. Direct constant.
A "constant" is a quantity that will not be modified when the program is running. 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.