C# interview questions and answers: - What is the difference between “==” and .Equals()?

When we create any object there are two parts to the object one is the content and the other is reference to that content.

So for example if you create an object as shown in below code:-

1. “.NET interview questions” is the content.
2. “o” is the reference to that content.

object o = ".NET Interview questions";

 “==” compares if the object references are same while “.Equals()” compares if the contents are same.

So if you run the below code both “==” and “.Equals()” returns true because content as well as references are same.

object o = ".NET Interview questions";

object o1 = o;

Console.WriteLine(o == o1);

Console.WriteLine(o.Equals(o1));

Console.ReadLine();

True

True

Now consider the below code where we have same content but they point towards different instances. So if you run the below code both “==”   will return false and “.Equals()”  will return true.

object o = ".NET Interview questions";

object o1 = new string(".NET Interview questions".ToCharArray());

Console.WriteLine(o == o1);

Console.WriteLine(o.Equals(o1));

Console.ReadLine();

False

True

When you are using string data type it always does content comparison. In other words you either use “.Equals()” or “==” it always do content comparison.

Enjoy this awesome youtube play list which covers 12 important .Net and c# interview question videos. 

You can also refer our blog which has more than 1000 .NET and c# interview questions with answer

Also see the following c# interview question video on Difference between == VS .Equals():-

CodeProject