Computer programming 1 pdf


In class-based programming, methods are defined in a class, and objects are instances of computer programming 1 pdf given class. One of the most important capabilities that a method provides is method overriding. Methods also provide the interface that other classes use to access and modify the data properties of an object.

Encapsulation and overriding are the two primary distinguishing features between methods and procedure calls. Method overriding and overloading are two of the most significant ways that a method differs from a conventional procedure or function call. Overriding refers to a subclass redefining the implementation of a method of its superclass. The various subclasses: rectangle, circle, triangle, etc.

Method overloading, on the other hand, refers to differentiating the code used to handle a message based on the parameters of the method. If one views the receiving object as the first parameter in any method then overriding is just a special case of overloading where the selection is based only on the first argument. Accessor methods are used to read data values of an object. Mutator methods are used to modify the data of an object. Manager methods are used to initialize and destroy objects of a class, e. These methods provide an abstraction layer that facilitates encapsulation and modularity. Initialization may include an acquisition of resources.

A destructor is a method that is called automatically at the end of an object’s lifetime, a process called destruction. Destruction in most languages does not allow destructor method arguments nor return values. Destruction can be implemented so as to perform cleanup chores and other tasks at object destruction. An abstract method is one with only a signature and no implementation body. It is often used to specify that a subclass must provide an implementation of the method. Abstract methods are used to specify interfaces in some computer languages. Class methods are methods that are called on a class rather than an instance.

They are typically used as part of an object meta-model. Special methods are very language-specific and a language may support none, some, or all of the special methods defined here. A language’s compiler may automatically generate default special methods or a programmer may be allowed to optionally define special methods. Most special methods cannot be directly called, but rather the compiler generates code to call them at appropriate times. Static methods are meant to be relevant to all the instances of a class rather than to any specific instance. They are similar to static variables in that sense.