“对"释放 std::vector 对象的方法 [英] "Right" way to deallocate an std::vector object

问题描述

第一个解决方案是:

std::vector<int> *vec = new std::vector<int>;
assert(vec != NULL);
// ...
delete vec;

替代方案是:

std::vector<int> v;
//...
vec.clear();
vec.swap(std::vector<int>(vec));

第二个解决方案有点诡计——什么是正确的"?怎么做?

The second solution's a bit of a trick --- what's the "right" way to do it?

我知道析构函数一旦离开堆栈就会被调用，我对其他方法很好奇.

I'm aware that the destructor will be called once it's off the stack, I was curious about other methods.

推荐答案

释放向量的最简单、最可靠的方法是在堆栈上声明它，然后什么都不做.

The simplest and most reliable way to deallocate a vector is to declare it on the stack and simply do nothing.

void Foo() {
  std::vector<int> v;
  ...
}

C++ 保证在方法执行时会调用v 的析构函数.std::vector 的析构函数将确保它分配的任何内存都被释放.只要 vector 的 T 类型具有适当的 C++ 释放语义，一切都会好起来的.

C++ guarantees that the destructor of v will be called when the method executes. The destructor of std::vector will ensure any memory it allocated is freed. As long as the T type of the vector<T> has proper C++ deallocation semantics all will be well.

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