如何编写一个可以接受数组或向量的函数? [英] How to write a function that can take in an array or a vector?

问题描述

我想编写一个带有一个参数的 C++ 函数，以便可以传入以下任一类型:

I would like to write a C++ function with one argument such that one can pass in either any of the following types:

std::vector<int>
std::array<int>
int array[numElements]
int *ptr = new int[numElements]
etc

模板是实现这一目标的最佳方式吗?

Would templating be the best way to accomplish this?

推荐答案

如果你希望能够做到 func(v) 你不能，因为我想不出你的函数可以推导出动态分配的int[numElements]的大小.

If you expect to just be able to do func(v) you cannot, because there's no way I can think of that your function could deduce the size of the dynamically allocated int[numElements].

包装它的一个好方法是采用一对前向迭代器，也就是说，如果您只需要一个一个地迭代项目，因为随机访问在某些容器上非常糟糕，例如 std::list.

A good way you could wrap this is to take a pair of forward iterators, that is, if you only need iterating over items one by one, since random access is very bad on some containers like std::list.

template<class FWIt>
void func(FWIt a, const FWIt b)
{
    while (a != b)
    {
        std::cout << "Value: " << *a << '\n';
        ++a;
    }
}

template<class T>
void func(const T& container)
{
    using std::begin;
    using std::end;
    func(begin(container), end(container));
}

这将适用于以下内容:

int array[5] = {1, 2, 3, 4, 5};
func(array);

int* dynarray = new int[5]{1, 2, 3, 4, 5};
func(dynarray, dynarray + 5);

std::vector<int> vec{1, 2, 3, 4, 5};
func(vec);
func(vec.begin(), vec.end());

std::list<int> list{1, 2, 3, 4, 5};
func(list);

由于@DanielH 的更改，这也可以通过直接传递原始数组而不是作为两个指针传递(但仍然不适用于动态分配的数组).

This also works by passing raw arrays directly rather than as two pointers thanks to @DanielH's change (but still won't work with dynamically allocated arrays).

这篇关于如何编写一个可以接受数组或向量的函数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！