These statements declare the instance variables age and weight to be of TYPE int (integer). The remaining data types offered in C are char (character) and float (floating-point number), as well as larger and higher-precision kinds of integer and floating-point variables.
A note about usage in this document: a DEFINITION is something which describes the structure of or allocates space for something, whereas a DECLARATION simply identifies the thing so the compiler is not confused. A struct expression may be thought of as "declaring" the instance variables and methods of a class. However, although no space is yet allocated for a Person object, the struct expression "defines" the Person class by describing its structure. (Definitions are usually implicitly declarations, while declarations need not define anything.)
Notice that a semicolon terminates simple C statements like the declaration 'int age;'. A compound statement like a function body is enclosed by {} braces and is not followed
