What about using var?

Question

Couldn't you just use var as parameter type? The compiler would decide the appropriate type then.

Answer 1

the compiler does not allow this because there is no context clues for the computer to figure out the actual data type of the parameter, which is required for you to use it in the function. that is why compilers require that you initialize var variables on the same line. if you really want to use a variable that could have any data type, just pass an object variable as the parameter. then you can cast it to call class specific methods and fields, or you could use the new c# 7.0 features to find the data type

https://blogs.msdn.microsoft.com/dotnet/2016/08/24/whats-new-in-csharp-7-0/

Answer 2

Because you can't use var as a valid data type as a parameter in the method signature.

public void Swap<T>(ref T a, ref T b) => Valid
public void Swap( ref var a, ref var b) => Invalid

Answer 3

variable