One of the most useful features of programming languages is their ability to take small building blocks and compose them. That's because the left side indicates the storage location where the result will go. Expressions do not represent storage locations, only values. A named storage location for values. All variables have a type, which is declared when the variable is created.
Every value belongs to one type.
The type of a variable determines which values can be stored there. A reserved word that is used by the compiler to parse programs. You cannot use keywords, like public , class and void as variable names. So far, the statements we have seen are declarations, assignments, and print statements. A statement that creates a new variable and determines its type.