Why use the 'ref' keyword when passing an object?

Question

If I am passing an object to a method, why should I use the ref keyword? Isn\'t this the default behaviour anyway?

For example:

class Program
{
    s         


        

Answer 1

Since TestRef is a class (which are reference objects), you can change the contents inside t without passing it as a ref. However, if you pass t as a ref, TestRef can change what the original t refers to. i.e. make it point to a different object.