模板约束C ++ [英] Template Constraints C++

问题描述

在C＃中，我们可以定义一个泛型类型，它对可以用作泛型参数的类型施加约束。以下示例说明了通用约束的用法：

 接口IFoo 
 {
} 
 
 
 class Foo< T>其中T：IFoo 
 {
} 
 
 class Bar：IFoo 
 {
} 
 
 class Simpson 
 {
} 
 
类程序
 {
 static void Main（string [] args）
 {
 Foo& a = new Foo< Bar>（）; 
 Foo< Simpson> b = new Foo< Simpson>（）; // error CS0309 
} 
} 
  

C ++ 0x本机支持C ++中的模板参数。

<但是我说的是目前的标准C ++。

解决方案

正如别人所说，C ++ 0x正在把这个内置于语言。在此之前，我建议您 Bjarne Stroustrup 的模板约束建议。

编辑： Boost 还有一个自己的替代品。

Edit2：看起来像概念已从C ++ 0x删除。

In C# we can define a generic type that imposes constraints on the types that can be used as the generic parameter. The following example illustrates the usage of generic constraints:

interface IFoo
{
}


class Foo<T> where T : IFoo
{
}

class Bar : IFoo
{
}

class Simpson
{
}

class Program
{
    static void Main(string[] args)
    {
        Foo<Bar> a = new Foo<Bar>();
        Foo<Simpson> b = new Foo<Simpson>(); // error CS0309
    }
}

Is there a way we can impose constraints for template parameters in C++.

---

C++0x has native support for this but I am talking about current standard C++.

解决方案

As someone else has mentioned, C++0x is getting this built into the language. Until then, I'd recommend Bjarne Stroustrup's suggestions for template constraints.

Edit: Boost also has an alternative of its own.

Edit2: Looks like concepts have been removed from C++0x.

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