CS-212 Classes (cont) Dick Steflik

Member functions Member functions of a class include – getters used to retrieve state data – setters used to set state data – mutators used to modify state data – functions that model the classes behavior tend to be action words (verbs or verb phrases) – take_off, reverse_direction, open...

Function prototypes Prototypes are models of how a function is to be called – are not necessarily part of the function definition, but may be float calculate_attack_angle (float, float); notice that in a prototype only the types are required, parameter names are not

Function signatures The signature of a function consists of: – returned type (if any) – the function name – the ordered set of types in the parameter list within its scope, a function’s signature must be unique even if its name is overloaded

Parameters Parameters are required on a function definition – parameter consists of a type and an identifier function formal parameters – parameters in the function definition alias names for the actual arguments scope is local to the function parameters may be passed to a function – by value – by reference ex. boolean exists(const point p);

Value Parameters “read only” or “input only” parameters makes a local copy (on the stack) of the value for use in the function; copies value of argument before running the function “pass by value” slower than pass by reference use only for small objects

Reference Parameters “read/write” parameter; value of argument can be changed uses address of argument to manipulate it doesn’t require local storage use & to identify reference parameters – remember & is the address operator ex. void rotate (point & p);

Reference Parameters (cont.) use const reference parameters instead of value parameters (faster), less memory rqd. const indicates a promise to not modify the reference parameter exists ex. double distance(const point & p); p is passed by reference as an input only parameter

Inlining functions Two ways: – inline keyword (place on function definition line) – replaces a call to the function with a copy of the function’s code. – defining the function in the class definition automatically makes it inline – use for small functions many calls to the function will bloat the program slightly faster than a regular function call

Function Overloading The function name may be reused (overloaded) within a class each definition must have a unique signature (pattern made up of function name and the parameter types)