Method Overloading with Optional Parameter

Question

I have a class as follows with two overload method.

Class A {     public string x(string a, string b)     {         return "hello" + a + b;     }      public string x(string a, string b, string c = "bye")     {         return c + a + b;     } } 

If I call the method x from another class with two parameters, then which method is going to execute and why? i.e,

string result = new A().x("Fname", "Lname"); 

I've tested this in my console application and the method with 2 parameters execute. Can someone explain this?

Answer 1

Use of named and optional arguments affects overload resolution:

If two candidates are judged to be equally good, preference goes to a candidate that does not have optional parameters for which arguments were omitted in the call. This is a consequence of a general preference in overload resolution for candidates that have fewer parameters.

Reference: MSDN

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Implying the above rule method with 2 parameters string x(string a,string b) will be called.

Note: If both overloaded methods have optional parameters then compiler will give compile-time ambiguity error.

Answer 2

If you call the Method with two Parameters, it uses the Method with two Parameters. If you'd call the one with three, it would use the other.