如何正确初始化模板类型的成员变量？ [英] How to correctly initialize member variable of template type?

问题描述

建议我具有如下模板功能：

suggest i have a template function like following:

template<class T>
void doSomething()
{
    T a; // a is correctly initialized if T is a class with a default constructor
    ...
};

但是，如果T是原始类型，则变量a不会被初始化。我可以写T a（0），但是如果T是一个类，则无法使用。在两种情况下（T ==类，T == int，char，bool等）都可以初始化变量吗？

But variable a leaves uninitialized, if T is a primitive type. I can write T a(0), but this doesn't work if T is a class. Is there a way to initialize the variable in both cases (T == class, T == int, char, bool, ...)?

推荐答案

像这样：

T a{};

---

Pre-C ++ 11，这是最简单的近似值：

---

Pre-C++11, this was the simplest approximation:

T a = T();

但是它要求 T 是可复制的（尽管该副本肯定会被删除）。

But it requires T be copyable (though the copy is certainly going to be elided).

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