C++ Good friend Perform
In C++ a perform or a complete class could also be declared to be a buddy of one other class or perform. Good friend perform may also be used for perform overloading.
Good friend perform declaration can seem wherever within the class. However an excellent observe can be the place the category ends. An odd perform that isn’t the member perform of a category has no privilege to entry the personal knowledge members, however the buddy perform does have the aptitude to entry any personal knowledge members. The declaration of the buddy perform may be very easy. The key phrase buddy within the class prototype inside the category definition precedes it.
Instance to Display working of buddy Perform
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/* C++ program to show the working of buddy perform.*/#embody <iostream>utilizing namespace std; class Distance {personal:int meter; public:Distance(): meter(0){ }buddy int func(Distance); //buddy perform };int func(Distance d){//perform definitiond.meter=10; //accessing personal knowledge from non-member functionreturn d.meter; }int important(){ Distance D;cout<<"Distace: "<<func(d);system("pause"); return=""></func(d);system("pause");></iostream> |
Program Output:
Right here, buddy perform func() is asserted inside Distance class. So, the personal knowledge could be accessed from this perform. Although this instance provides you what concept in regards to the idea of buddy perform.
In C++, buddy means to present permission to a category or perform. The non-member perform has to grant an entry to replace or entry the category.
The benefit of encapsulation and knowledge hiding is {that a} non-member perform of the category can not entry a member knowledge of that class. Care should be taken utilizing buddy perform as a result of it breaks the pure encapsulation, which is without doubt one of the benefits of object oriented programming. It’s best used within the operator overloading.
C++ Digital Perform
Polymorphism is refers back to the property by which objects belonging to totally different lessons are ready to reply to the identical message however in numerous kinds. When there are C++ capabilities with identical title in each tremendous class in addition to sub class, digital capabilities provides programmer functionality to name member perform of various class by a identical perform name based mostly upon totally different context. This characteristic is called polymorphism which is without doubt one of the necessary options of OOP. Pointer can be one of many key features of C++ language just like that of C. On this chapter we will probably be coping with digital capabilities and pointers of C++.
What’s Digital Perform?
A digital perform is a particular type of member perform that’s declared inside a base class and redefined by a derived class. The key phrase digital is used to create digital perform, precede the perform’s declaration within the base class. If a category features a digital perform and if it will get inherited, the digital class redefines a digital perform to go together with its personal want. In different phrases, a digital perform is a perform which will get override within the derived class and instructs the C++ compiler for executing late binding on that perform. Perform name is resolved at run time in late binding and so compiler determines the kind of object at run time.
Program for Digital Perform:
Instance:
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#embody <iostream>utilizing namespace std; class b{public: digital void present() { cout<<"n Displaying base class....";}void show() {cout<<"n Displaying base class...." ;} }; class d:public b {public: void show(){ cout<<"n Displaying derived class....";} void present() { cout<<"n Displaying derived class...."; }};int important() { b B; b *ptr; cout<<"nt P points to base:n" ; ptr=&B; ptr->show(); ptr->present(); cout<<"nnt P points to drive:n"; d D; ptr=&D; ptr->show(); ptr->present();}</iostream> |
