Each name in the list has the type defined by the type specifier. A definition may (optionally) provide an initial value for one or more of the names it defines

int sum = 0, value, // sum, value, and units_sold have type int
units_sold = 0; // sum and units_sold have initial value 0
Sales_item item; // item has type Sales_item (see § 1.5.1 (p. 20))
// string is a library type, representing a variable-length sequence of characters
std::string book("0-201-78345-X"); // book initialized from string literal