C# default value

Question

private static void print(StreamWriter sw, string mlog, bool screen)
    {
        DateTime ts = DateTime.Now;
        sw.WriteLine(ts + " " + mlog);
        if (screen == true)
        {
            Console.WriteLine(mlog);
        }
    }

I would use print (sw,"write here", false) to call. 90% chance I will use false. how to make it the default to be false that way I dont have to do the extra type when I do the call?

Sometimes its better to have explicit methods, eg PrintToStream() and PrintToStreamAndScreen() — Chris Moutray
– Chris Moutray, Commented Jul 2, 2012 at 19:06

Jon Skeet · Accepted Answer · 2012-07-02 19:00:32Z

7

If you're using C# 4, you can make screen an optional parameter:

// Note: changed method and parameter names to be nicer
private static void Print(StreamWriter writer, string log, bool screen = false)
{
    // Note: logs should almost always use UTC rather than the system local
    // time zone
    DateTime now = DateTime.UtcNow;

    // TODO: Determine what format you want to write your timestamps in.
    sw.WriteLine(CultureInfo.InvariantCulture,
                 "{0:yyyy-MM-dd'T'HH:mm:ss.fff}: {1}", now, log);
    if (screen)
    {
        Console.WriteLine(mlog);
    }
}

answered Jul 2, 2012 at 19:00

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

user166390 Over a year ago

I've been converting more of my code to use DateTimeOffset rather than UTC DateTime .. I find it less confusing later to convert/know the "appropriate" local time. Not necessarily relevant here, but not many people seem to know about it.

Jon Skeet Over a year ago

@pst: I'd recommend you convert to using Noda Time where it's all clearer to start with :)

user166390 Over a year ago

Haha, thanks. I didn't know there was such a library for .NET.

John Ryann Over a year ago

@JonSkeet thanks.why should I use UtcNow instead of Now? Pros and cons

Jon Skeet Over a year ago

@JohnRyann: In my experience, logging in UTC is simpler in all respects. It's friendlier for machine readability, and means you don't need to worry about what time zone the machine happened to be in at the time. Oh, and you don't get logs that go backwards around DST transitions...

Miroslav Popovic · Accepted Answer · 2012-07-02 19:00:30Z

1

Just use = false:

private static void print(StreamWriter sw, string mlog, bool screen = false)

Here's a little more info on Named and Optional Arguments in C#.

Note that this is new in C# 4.0. For older versions, use method overloads as others have suggested.

answered Jul 2, 2012 at 19:00

Miroslav Popovic

12.1k2 gold badges38 silver badges48 bronze badges

Comments

user845279 · Accepted Answer · 2012-07-02 19:01:43Z

1

private static void print(StreamWriter sw, string mlog)
{
    print(sw, mlog, false);
}

answered Jul 2, 2012 at 19:01

user845279

2,8041 gold badge22 silver badges38 bronze badges

Comments

Alexei Levenkov · Accepted Answer · 2012-07-02 19:02:32Z

1

For older versions you can simply provide 2 overrides:

private static void print(StreamWriter sw, string mlog)
{ 
 print(sw,mlog, false);
}

answered Jul 2, 2012 at 19:02

Alexei Levenkov

101k15 gold badges138 silver badges189 bronze badges

Comments

Monroe Thomas · Accepted Answer · 2012-07-02 19:03:03Z

1

If you aren't using C# 4, create a function overload:

private static void Print(StreamWriter writer, string log) 
{ 
    Print(writer, log, false);
}

answered Jul 2, 2012 at 19:03

Monroe Thomas

5,0421 gold badge19 silver badges21 bronze badges

Comments

Sam Axe · Accepted Answer · 2012-07-02 19:04:46Z

1

The answers involving optional parameters will work, but some languages do not support optional parameters, so they could not call this method from a public-facing API.

I would go with method overloading..

private static void print(StreamWriter sw, string mlog) {
    print(sw, mlog, false);
}

private static void print(StreamWriter sw, string mlog, bool screen) { ... }

answered Jul 2, 2012 at 19:04

Sam Axe

33.8k10 gold badges60 silver badges92 bronze badges

2 Comments

Tim S. Over a year ago

True, and a good principle to remember. This case, however, is a private method, so I don't think you really need to consider that.

Sam Axe Over a year ago

@TimS. agreed in this instance. If it were to become a public method they may want to consider overloading.

Blackstar · Accepted Answer · 2012-07-02 20:07:25Z

1

private static void print(StreamWriter sw, string mlog = "Write here", bool screen = false)
    {
        DateTime ts = DateTime.Now;
        sw.WriteLine(ts + " " + mlog);
        if (screen == true)
        {
            Console.WriteLine(mlog);
        }
    }

answered Jul 2, 2012 at 20:07

Blackstar

1611 silver badge15 bronze badges

Collectives™ on Stack Overflow

C# default value

7 Answers 7

5 Comments

Comments

Comments

Comments

Comments

2 Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

5 Comments

Comments

Comments

Comments

Comments

2 Comments

Comments

Related