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C# 객체 비교

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객채 비교 🎰

class EqualsPerson : IEquatable<EqualsPerson>
{
	public string PersonalID { get; set; }
	public string Name { get; set; }
	public int Age { get; set; }              

	public override bool Equals(object obj)
	{
		return this.Equals(obj as EqualsPerson);
	}

	public bool Equals(EqualsPerson other)
	{
		if (other is null)
			return false;

		if (Object.ReferenceEquals(this, other))
			return true;

		return this.PersonalID == other.PersonalID;
	}

	public static bool operator ==(EqualsPerson left, EqualsPerson right)
	{
		if (left is null)
		{
			if (right is null) 
				return true; 

			return false;
		}

		return left.Equals(right);
	}

	public static bool operator !=(EqualsPerson left, EqualsPerson right) => !(left == right);

	public override int GetHashCode()
	{
		var hashCode = 1345254698;
		hashCode = hashCode * -1521134295 + EqualityComparer<string>.Default.GetHashCode(PersonalID);
		hashCode = hashCode * -1521134295 + EqualityComparer<string>.Default.GetHashCode(Name);
		hashCode = hashCode * -1521134295 + Age.GetHashCode();
		return hashCode;
	}

	public override string ToString() => $"PersonalID : {PersonalID}, Name : {Name}, Age : {Age}";
}

Main

// NormalPerson은 IEquatable이 구현되지 않은 클래스이다.
static void Main(string[] args)
{  
	var person1 = new NormalPerson()
	{
		PersonalID = "1",
		Name = "홍길동",
		Age = 24,
	};

	var person2 = new NormalPerson()
	{
		PersonalID = "1",
		Name = "이몽룡",
		Age = 25,
	}; 

	var person3 = person1;

	Console.WriteLine("=== NormalPerson ===");
	Console.WriteLine($"person1 : {person1.ToString()}");
	Console.WriteLine($"person2 : {person2.ToString()}");
	Console.WriteLine($"person3 : {person3.ToString()}");
	Console.WriteLine($"person1 == person 2 : {person1.Equals(person2)}");
	Console.WriteLine($"person1 == person 3 : {person1.Equals(person3)}");
	Console.WriteLine(""); 

	var ePerson1 = new EqualsPerson()
	{
		PersonalID = "1",
		Name = "홍길동",
		Age = 24,
	};

	var ePerson2 = new EqualsPerson()
	{
		PersonalID = "1",
		Name = "이몽룡",
		Age = 25,
	};

	var ePerson3 = ePerson1;

	Console.WriteLine("=== EqualsPerson ===");
	Console.WriteLine($"ePerson1 : {ePerson1.ToString()}");
	Console.WriteLine($"ePerson2 : {ePerson2.ToString()}");
	Console.WriteLine($"ePerson3 : {ePerson3.ToString()}");
	Console.WriteLine($"ePerson1 == ePerson 2 : {ePerson1.Equals(ePerson2)}");
	Console.WriteLine($"ePerson1 == ePerson 3 : {ePerson1.Equals(ePerson3)}"); 
}

결과

equals