Types of polymorphism - temporary, contained, parameterized and coercive-C++-php.cn

Types of polymorphism - temporary, contained, parameterized and coercive

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Release： 2023-09-23 10:21:04

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多态性的类型 - 临时、包含、参数化和强制

Here we will see different types of polymorphism. Type is -

Ad-Hoc
Contains
Parameterized
Mandatory

Ad-Hoc Multiple Morality is called overloading. This allows functions with the same name to act differently for different types. Both functions and operators can be overloaded. Some languages do not support operator overloading, but function overloading is common.

Example

#include<iostream>
using namespace std;
int add(int a, int b) {
   return a + b;
}
string add(string a, string b) {
   return a + b; //concatenate
}
int main() {
   cout << "Addition of numbers: " << add(2, 7) << endl;
   cout << "Addition of Strings: " << add("hello", "World") << endl;
}

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Output

Addition of numbers: 9
Addition of Strings: helloWorld

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Inclusion of polymorphism is called subtyping. This allows the use of base class pointers and references to point to derived classes. This is runtime polymorphism. We don't know the actual object type before execution. We need virtual functions in C to achieve this inclusion polymorphism.

Example

#include<iostream>
using namespace std;
class Base {
   public:
      virtual void print() {
         cout << "This is base class." << endl;
      }
};
class Derived : public Base {
   public:
      void print() {
         cout << "This is derived class." << endl;
      }
};
int main() {
   Base *ob1;
   Base base_obj;
   Derived derived_obj;
   ob1 = &base_obj; //object of base class
   ob1->print();
   ob1 = &derived_obj; //same pointer to point derived object
   ob1->print();
}

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Output

This is base class.
This is derived class.

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Forced polymorphism is called a cast. This type of polymorphism occurs when an object or primitive is converted to some other type. There are two types of casting. Implicit conversions are done using the compiler itself, explicit conversions are done using const_cast, dynamic_cast, etc.

Example

#include<iostream>
using namespace std;
class Integer {
   int val;
   public:
      Integer(int x) : val(x) {
   }
   operator int() const {
      return val;
   }
};
void display(int x) {
   cout << "Value is: " << x << endl;
}
int main() {
   Integer x = 50;
   display(100);
   display(x);
}

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Output

Value is: 100
Value is: 50

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Parameter polymorphism is called early binding. This type of polymorphism allows using the same code for different types. We can get it by using templates.

Example

#include<iostream>
using namespace std;
template <class T>
T maximum(T a, T b) {
   if(a > b) {
      return a;
   } else {
      return b;
   }
}
int main() {
   cout << "Max of (156, 78): " << maximum(156, 78) << endl;
   cout << "Max of (A, X): " << maximum(&#39;A&#39;, &#39;X&#39;) << endl;
}

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Output

Max of (156, 78): 156
Max of (A, X): X

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