How Can a Constructor be Returned in C#?

[Silicon Waffle]

I find that people can do this in C#

public decimal func()
{
    return new Decimal(...)
}

and use it like this

Console.Writeline("{0}",func());

My question is how can the constructor returned in func() be output like that ? Thank you.

 

[Mark44]

I find that people can do this in C#

public decimal func()
{
    return new Decimal(...)
}

and use it like this

Console.Writeline("{0}",func());

My question is how can the constructor returned in func() be output like that ? Thank you.

The constructor is not being returned. In the call to Writeline, the expression func() is evaluated, which causes the Decimal constructor to be called. The Decimal constructor creates an instance of a Decimal struct and returns it to the caller, func().

In your func() definition, shouldn't the header be public Decimal func()?

 

[Borg]

I find that people can do this in C#

public decimal func()
{
    return new Decimal(...)
}

and use it like this

Console.Writeline("{0}",func());

My question is how can the constructor returned in func() be output like that ? Thank you.

Does it make more sense to you if it's written this way? It's the same thing as what you wrote.

public decimal func()
{
    decimal dec = new Decimal(...);
    return dec;
}

 

[Silicon Waffle]

Does it make more sense to you if it's written this way? It's the same thing as what you wrote.

public decimal func()
{
    decimal dec = new Decimal(...);
    return dec;
}

Yes, but I'd still like to know what is "dec" that is being returned. I don't think it's a raw number being fed into WriteLine.
Well, the constructor is like this, for example,

//...
bits[4]={2422422,28225,0,0};
return new Decimal (18,2,false,bits);

 

[Silicon Waffle]

The constructor is not being returned. In the call to Writeline, the expression func() is evaluated, which causes the Decimal constructor to be called. The Decimal constructor creates an instance of a Decimal struct and returns it to the caller, func().

In your func() definition, shouldn't the header be public Decimal func()?

Thank you Mark44, it should be Decimal in that line.

 

[Silicon Waffle]

Actually I think it is a string, not a number that is being passed into WriteLine. But I don't know when it has been converted to a string ?
This seems more understandable

dec=new Decimal(...);
return dec.Value;

 

[Filip Larsen]

I find that people can do this in C#

public decimal func()
{
    return new Decimal(...)
}

and use it like this

Console.Writeline("{0}",func());

My question is how can the constructor returned in func() be output like that ? Thank you.

Your func() returns an instance of the value type Decimal [1,2] which is boxed [3] in the call to Console.Writeline [4] (since its a value type [5]) and then finally converted to a string within the Console.Writeline method by one of the Decimal.ToString methods. By the way, note that decimal is shorthand for System.Decimal.

[1] https://msdn.microsoft.com/en-us//library/364x0z75.aspx
[2] https://msdn.microsoft.com/en-us/library/system.decimal.aspx
[3] https://msdn.microsoft.com/en-us/library/yz2be5wk.aspx
[4] https://msdn.microsoft.com/en-us/library/586y06yf.aspx
[5] https://msdn.microsoft.com/en-us/library/s1ax56ch.aspx