# What's going on here?

**URL:** <https://forum.kirupa.com/t/whats-going-on-here/269123>\
**Category:** programming\
**Created:** [August 23, 2008, 12:05am UTC](https://forum.kirupa.com/t/whats-going-on-here/269123 "2008-08-23T00:05:41Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![kdd](https://avatars.discourse-cdn.com/v4/letter/k/ecb155/32.png) [@kdd](https://forum.kirupa.com/u/kdd)\
**Post date:** [August 23, 2008, 12:05am UTC](https://forum.kirupa.com/t/whats-going-on-here/269123/1 "2008-08-23T00:05:41Z")

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[http://www.java2s.com/Tutorial/CSharp/0120\_\_struct/Usethistoreferencestructsconstructor.htm](http://www.java2s.com/Tutorial/CSharp/0120__struct/Usethistoreferencestructsconstructor.htm)

In the 2nd constructor, this is used. Can anyone please explain what’s going on there?

Thanks! 🙂

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**Author:** ![skOOb](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@skOOb](https://forum.kirupa.com/u/skOOb)\
**Post date:** [August 24, 2008, 1:16am UTC](https://forum.kirupa.com/t/whats-going-on-here/269123/2 "2008-08-24T01:16:49Z")

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Function Overloading. You can create an instance of the class with either one parameter, or two since it is being defined there. In their example they used two, but they could have used one and not received an error. Search for function overloading and it should explain much better than me.

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**Author:** ![kdd](https://avatars.discourse-cdn.com/v4/letter/k/ecb155/32.png) [@kdd](https://forum.kirupa.com/u/kdd)\
**Post date:** [August 24, 2008, 5:05am UTC](https://forum.kirupa.com/t/whats-going-on-here/269123/3 "2008-08-24T05:05:16Z")

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Sorry, I wasn’t very clear. I meant what’s going on here:

```auto
public ComplexNumber( double real ):this( real, 0 )

```

What is “: this” doing after the function definition?

Thanks! 🙂

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**Author:** ![TheCanadian](https://avatars.discourse-cdn.com/v4/letter/t/67e7ee/32.png) [@TheCanadian](https://forum.kirupa.com/u/TheCanadian)\
**Post date:** [August 24, 2008, 4:38pm UTC](https://forum.kirupa.com/t/whats-going-on-here/269123/4 "2008-08-24T16:38:45Z")

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[http://forums.msdn.microsoft.com/en-US/csharplanguage/thread/560ca9d9-1ef3-4aae-b0a7-aa029da66b99/](http://forums.msdn.microsoft.com/en-US/csharplanguage/thread/560ca9d9-1ef3-4aae-b0a7-aa029da66b99/)