为什么我没有得到ref关键字的错误

Question

According to definition, ref keyword must be initialized before passing. while out parameters must be initialized before returning from the function.

Below is my snippet.

   public void TestRef(ref string n)
    {

    }

    public void TestOut(out string n)
    {

        n = "Hello"; //if I don't initialize, I gets compile time error. & That's right.

    }

Now while calling the methods.

string name;
TestOut(out name);//fine
TestRef(ref name) // why not throwing error.

In the above calls when trying to call TestRef() I have not initialized name parameter. But as per my understanding ref parameter must be initialized before passing.

It builds & run with no errors.

Answer 1

TestOut guarantees that name variable will be initialized when method will finish execution

See out keyword

Although variables passed as out arguments do not have to be initialized before being passed, the called method is required to assign a value before the method returns

and ref

An argument that is passed to a ref parameter must be initialized before it is passed. This differs from out parameters, whose arguments do not have to be explicitly initialized before they are passed. For more information, see out.

Reorder the method calls and you will see the behavior you expect.

Answer 2

Calling the TestOut method first guarantees the initialization of the name variable. Reorder the method calls and you will see the behavior you expect.

Answer 3

comment out the line TestOut(out name);//fineTestOut(out name);//fine You will get error for the following lines string name; TestRef(ref name) // why not throwing error.