Not only is it syntactically legal to write code in the header files: Templated code has to go there.
[quote name='Álvaro' timestamp='1355249382' post='5009481']
Not only is it syntactically legal to write code in the header files: Templated code has to go there.
The C# interface-implementation combination seems to violate DRY exactly as much as a pure virtual class and an inheriting concrete class do in C++. Your point was...?
You misinterpreted ChaosEngine.
It's not about the C++ runtime model (on which the pure virtual class acts like an interface indeed), what he criticized was the source code allegedly separation between declaration (header files) and implementation (.cpp files), which IMO violates the DRY principle.
More so, AFAIK the compiler and the preprocessor don't enforce this source code separation, so it's sintatically legal to write code in the header files.
[/quote]Correct. But ChaosEngine said a C# interface is a much cleaner expression of intent than a C++ header file, and my counterpoint was that you can write an equivalent expression in a C++ header file that is not appreciably "less clean". A class which contains nothing but public virtual functions is an interface; there's no way to confuse it for anything else.
The C# interface-implementation combination seems to violate DRY exactly as much as a pure virtual class and an inheriting concrete class do in C++. Your point was...?
[quote name='Bubsy' timestamp='1355249217' post='5009479']
You misinterpreted ChaosEngine.
It's not about the C++ runtime model (on which the pure virtual class acts like an interface indeed), what he criticized was the source code allegedly separation between declaration (header files) and implementation (.cpp files), which IMO violates the DRY principle.
More so, AFAIK the compiler and the preprocessor don't enforce this source code separation, so it's sintatically legal to write code in the header files.
[/quote]Correct. But ChaosEngine said a C# interface is a much cleaner expression of intent than a C++ header file, and my counterpoint was that you can write an equivalent expression in a C++ header file that is not appreciably "less clean". A class which contains nothing but public virtual functions is an interface; there's no way to confuse it for anything else.
[/quote]
You misinterpreted, it's .h/.cpp source code schema that violates the DRY principle, not the pure virtual base class and its concrete implementation. It's the definition of a single/complete entity into two or more files that is being criticized by me.
My statement that template code has to go into a header is basically true in practice (at least it has to go there in the place where I work, in the standard library implementation and in Boost).
Correct. But ChaosEngine said a C# interface is a much cleaner expression of intent than a C++ header file, and my counterpoint was that you can write an equivalent expression in a C++ header file that is not appreciably "less clean". A class which contains nothing but public virtual functions is an interface; there's no way to confuse it for anything else.
Yeah the real issue to me isn't the [font=courier new,courier,monospace].h/.cpp[/font] schism, but the actual way in which C++ code is compiled. #include just means copy&paste, whereas in other languages, including a module is a higher level construct. I've often seen CPP files that are 60k lines long, after all the #includes have been resolved... (hence crap like [font=courier new,courier,monospace]WIN32_LEAN_AND_MEAN[/font] being invented). No matter what kind of [font=courier new,courier,monospace].h/.cpp[/font] organisation you use, you can't fix the compilation model (nor the fact that so much of the ABI is implementation defined, which keeps C around for interop).
You could argue that the separation between declaration and implementation is built into the language in C# and java using interfaces, as opposed to C++s frankly demented compilation model.
//foo.h
#pragma once
class IFoo
{
public:
static IFoo* New();
virtual ~IFoo() {}
virtual void Frobnicate() = 0;
};
//foo.cpp
class Foo : public IFoo
{
int member;
void Frobnicate()
{
member = 42;
printf("hello world");
}
};
IFoo* IFoo::New() { return new Foo; }p.s. it's not my cup of tea though.
how would you replace the goto in this bit with an exception
for (int bar =0; bar < 100; ++bar)
{
for(int foo = 0; foo < 100; ++foo)
{
if (foo * bar == 100)
{
goto loopBreak;
}
}
}
loopBreak:
printf("%d", 100);
Try writing your own parser for the language...
Almost everyone LOVES Java and hates C, C++,
