In this blog, we will learn what is Diamond problem in c# and We will learn Diamond problem in c# with a simple example.
Prerequisites:
Why c# does not supports multiple inheritances?
One of the main reason behind this is the “diamond problem”.
What is the Diamond Problem:
The "diamond problem" is an ambiguity that arises when two classes B and C inherit from A, and class D inherits from both B and C. If there is a method in A that B and C have overridden, and D does not override it, then which class of the method does D inherit: that of B, or that of C? So this is an ambiguity problem in multiple inheritances in c#. So that c# does not support multiple inheritances.
Example 1:
This is a simple example to understand the concepts of the diamond problem in c#.
First of all, we will check when does the diamond problem will arise with programmatically.
We will be creating class A, class B, class C, class D having Print() method in the base class. The class B and C inherits from class A. and class D inherit from class B and Class C as follow.
using System;
namespace CSharpConsoleApp.DiamondProblemExample
{
public class A
{
public virtual void Print()
{
Console.WriteLine("Print method of class A.");
}
}
public class B: A
{
public override void Print()
{
Console.WriteLine("Print method of class B");
}
}
public class C: A
{
public override void Print()
{
Console.WriteLine("Print method of class C");
}
}
// Error: D class can not have multiple base classes.
public class D: C, B
{
}
class DiamondProblemExample
{
static void Main(string[] args)
{
D obj = new D();
obj.Print();
}
}
}
How can we resolve the diamond problem in c#?
We can resolve the diamond problem by using Interface in c#.
Example 2:
using System;
namespace CSharpConsoleApp.DiamondProblemExample
{
interface IA
{
void PrintIA();
}
interface IB
{
void PrintIB();
}
interface IC
{
void PrintIC();
}
public class A : IA
{
public void PrintIA()
{
Console.WriteLine("PrintIA method from class A.");
}
}
public class B:IB
{
public void PrintIB()
{
Console.WriteLine("PrintIB method from class B.");
}
}
public class C:IC
{
public void PrintIC()
{
Console.WriteLine("PrintIC method from class C.");
}
}
public class D: IA, IB,IC
{
public void PrintIA()
{
Console.WriteLine("PrintIA method from class D.");
}
public void PrintIB()
{
Console.WriteLine("PrintIB method from class D.");
}
public void PrintIC()
{
Console.WriteLine("PrintIC method from class D.");
}
}
class DiamondProblemExample
{
static void Main(string[] args)
{
D obj = new D();
obj.PrintIA();
obj.PrintIB();
obj.PrintIC();
Console.ReadLine();
}
}
}
OutPut:
Real Time Diamond Problem in C# Example:
Real Time Diamond Problem in C# Solution:
A real-time example of resolving a diamond problem by using Interface in c#.
using System;
namespace CSharpConApp.DiamondProblem1
{
interface IMother
{
void Loan();
}
interface IFather
{
void Loan();
}
public class Mother:IMother
{
public void Loan()
{
Console.WriteLine("Loan taken by mother.");
}
}
public class Father:IFather
{
public void Loan()
{
Console.WriteLine("Loan taken by father");
}
}
public class Child:IMother,IFather
{
void IMother.Loan()
{
Console.WriteLine("Mother's loan paid by child");
}
void IFather.Loan()
{
Console.WriteLine("Father's loan paid by child");
}
}
public class DiamondProblem1
{
static void Main(string[] args)
{
Child child = new Child();
((IMother)child).Loan();
((IFather)child).Loan();
Console.ReadLine();
}
}
}
Output:
To understand the concepts of Implicit and Explicit interface visit the following link.
I hope you understood the concept of the diamond problem in C#.
