Each variable or expression has its own data type, for example, an declaration
Indicates that the variable
has an integer type
The declaration allows you to enter a variable in the program. This variable will have a certain type of data: integer, floating point, character in the case of basic data types, or custom type (data structure, class). The type of the variable defines the set of operations that can be performed on the variable. The declaration of a variable determines the allocation of the memory area that is required for it. And also the value of this variable, which from the computer's point of view will be a sequence of bits. The declaration of a variable also carries the name by which the programmer will refer to this variable in the program code.
In the above example, we have a variable that has a base integer type, with which arithmetic operations, comparison, assignment, etc. can be performed. Refer to the code in this code by this name by some_variable.