What is the difference between == and .Equals() in C#?

Question

Accepted Answer

**==** — operator, can be overloaded. **.Equals()** — method, can be overridden.

**For value types:**
- Both compare values.
- Same result.

```csharp
int a = 5, b = 5;
a == b;      // true
a.Equals(b); // true
```

**For reference types (default):**
- **==** — compares references (same object).
- **.Equals()** — compares references (same object).

```csharp
string s1 = "hello";
string s2 = new string(new char[] {'h', 'e', 'l', 'l', 'o'});

s1 == s2;      // true (string overloads ==)
s1.Equals(s2); // true (string overrides Equals)
```

**Custom class (default):**
```csharp
class Person {
    public string Name;
}

var p1 = new Person { Name = "Alice" };
var p2 = new Person { Name = "Alice" };

p1 == p2;      // false (different references)
p1.Equals(p2); // false (different references)
```

**Overriding behavior:**
- **==** — overload with operator keyword.
- **.Equals()** — override in class.

**Best practice:**
- Use **==** for reference equality.
- Use **.Equals()** for value equality.

C#: What is the difference between == and .Equals() in C#?