Typedef in C#?

[j.ignatius]

I'm new to C# and come from a C++ background. C++ allows you to define
new types very easily like this:

typedef char array25_t[25];

which defines a type called array25_t that contains up to 25 chars.

Does a similar typedef also exist in C#? Or do you have to define a
new class and assign member variables?

 

[shiv_koirala]

look for structures

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[Lebesgue]

There is no typedef in C#.

 

[James Curran]

typedef char array25_t[25];

which defines a type called array25_t that contains up to 25 chars.

Does a similar typedef also exist in C#? Or do you have to define a
new class and assign member variables?

Not in C# v1.0.

In C# v2.0 (due out next month), you can do something similar with the
"using" directive.
Your example would translate to
using array25_t = char[25];

Except that still won't work, because the real problem is the "char[25]"
which is not allowed in C#.

 

[Jon Skeet [C# MVP]]

typedef char array25_t[25];

which defines a type called array25_t that contains up to 25 chars.

Does a similar typedef also exist in C#? Or do you have to define a
new class and assign member variables?

Not in C# v1.0.

In C# v2.0 (due out next month), you can do something similar with the
"using" directive.
Your example would translate to
using array25_t = char[25];

Except that still won't work, because the real problem is the "char[25]"
which is not allowed in C#.

Has the using directive changed in 2.0 other than in terms of generics?
You can already do something like:

using Foo = System.String;

if you want in 1.1, although it's relatively rarely useful IME.

In 2.0 it's useful due to being able to do things like:

using NameAgeMap = System.Collections.Generic.Dictionary<string,int>;

Unfortunately, it doesn't stop you from doing:
using NameHeightMap =System.Collections.Generic.Dictionary<string,int>;

and then:

NameAgeMap x = new NameHeightMap();

Never mind

 

[riscy]

Jon, wondering what wrong with that :- NameAgeMap x = new
NameHeightMap() ?
Regards
Riscy

 

[Jon Skeet [C# MVP]]

Jon, wondering what wrong with that :- NameAgeMap x = new
NameHeightMap() ?

Well, there's nothing wrong as far as the compiler is concerned - but
clearly a height isn't the same as an age, so it doesn't make semantic
sense. It's as wrong as doing:

person.Height = person.Age;

Yes, they might both be integers, but as humans we know that they're
different types - a length of time isn't the same as a height.