Can function overload with different return type...?

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Hi I am a beginner in C# & .NET.
In the following code CreateCountry function declared as int and its return type is also int (this part I got it)

But I am confused about the overloaded string variable in int function, also nowhere in this piece of code the given string is converted to int value.

Please guide me. Thank you (Reference:CRUD project)

C#

public int CreateCountry(string countryName)
{
   if (string.IsNullOrEmpty(countryName))
   {
       return -1;
   }
   else
   {
        DALCountry dalCountry = new DALCountry();
        return dalCountry.CreateCountry(countryName);
   }            
}

Posted 20-Nov-15 3:20am

Member 11633058

Updated 20-Nov-15 3:37am

phil.o

v2

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Foothill · Answer 1 · 2015-11-20T03:51:00

It would be better design to check the country argument and throw an exception if it's not right. The calling function would have a try/catch block to handle the error.

C#

public DALCountry CreateCountry(string countryName)
{
  if (String.IsNullOrEmpty(countryName))
    throw new ArgumentException("countryName");

  DALCountry dalCountry = new DALCountry();
  return dalCountry.CreateCountry(countryName);
}

Dave Kreskowiak · Answer 2 · 2015-11-20T04:31:00

Solution 3

Your question doesn't make a lot of sense.

Are you asking how to overload a method with a copy that takes the same parameter type, a string in your case, and differs only by the return type? Are you asking how a method can return either an integer OR a DALCountry type?

It's easy. You can't. You must plan your code better. A method can only ever return a single type. It cannot return multiple types. Solution #1 is the best solution as a DALCountry class can hold much more meaningful information than a single integer can ever hold.

Posted 20-Nov-15 4:31am

Dave Kreskowiak

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Member 11633058 20-Nov-15 16:29pm

Yes, I want to ask that, how can you overload a method with a copy that takes the same parameter type, (a string in this case), and differs by the return type(int in this case)?

Dave Kreskowiak 20-Nov-15 18:16pm

Go back and reread my post. YOU CAN'T DO THAT! It's impossible for the runtime to figure out which overload to call because the parameter lists are identical. The runtime also cannot call every overload to see which one should be the valid return value. What you want cannot be done.

Member 11633058 21-Nov-15 6:57am

Thank you Dave! thanks for the guidance

BillWoodruff · Answer 3 · 2015-11-20T09:31:00

'CreateCountry is not "declared as int." It returns an 'int, and it takes a 'string parameter.

The 'CreateCountry method in the 'DALCountry class must be different from the 'CreateCountry method you show here, or: the method would call itself recursively until there was a stack overflow error.

There is no "overloaded string variable" here.

Rene Bustos · Answer 4 · 2015-11-20T04:01:00

C#

Hello.
you can not see the conversion from String to integer, because it is a class method : DALCountry .

DAL , stands for: Data Access Layer .

The conversion of " countryname " to integer data type , can be given in different ways, but the most is roughly a query to the database : "SELECT ID FROM WHERE CountryName Country = 'USA'"

With the above query, an identifier is obtained for countryName
And that outcome , which will return the function CreateCountry

And I hope it helped you on your question 

Best regards From Mexico.

Can function overload with different return type...?

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