Use of const keyword in C#

Question

Why we can only use const keyword with primitive type in C# and cannot be used with user-defined types? Moreover, what is the concept that const are static by-default?

Amit Mohanty · Answer

Hey, check the below link. this may clear you doubt. https://www.onlinebuff.com/article_understand-constants-in-c-with-an-example_51.html

Sachin Singh · Answer

Okay. 1 Kilometer=1000 meters, can you change it? No , this is universal contant. Pie= 3.14, can you change it? Yes , you can take n numbers after decimal (3.142567). This is partial constant. So, whenever you are dealing with universal constant that will never ever change, you use const. when you need some values to change but only at runtime you use readonly, you set the value at configuration and read it inside the class constructor. Now, Why we can only use const keyword with primitive type Ans:- Primitive types are value types, means they can not be changed by chaging the value to their location. ex:- int x=10; int y=x; // y=10 x++; // x=11 Console.Write(y); // still 10 so, compiler assign the value at the compile time, you can test it using ILDASM tool, (go to cmd-->Ildasam pathof your exe/class). That is the reason, Const are called compile time constant. This is not possible with reference type like userdefined datatype like class or even struct.