C++从函数返回数组
我需要将一个数组读入我的函数，提取数据，然后从函数返回一个数组.
I need to read in an array to my function, extract the data, and then return an array from the function.
该数组只能保存 2 个值.
The array will only ever hold 2 values.
这是我想做的概念:
int myfunction(int my_array[1])
{
int f_array[1];
f_array[0] = my_array[0];
f_array[1] = my_array[1];
// modify f_array some more
return f_array;
}
我已经阅读了有关指针等的信息，但非常困惑，希望能有一个非常基本的例子来说明如何最好地解决这个问题！
I've read up about pointers etc but have got very confused and would appreciate a really basic example of how best to approach this!
谢谢！
推荐答案
你不能在c++中返回n个内置数组.
You can't return n builtin array in c++.
如果您是 C++ 新手并且对指针感到困惑，那么您真的不想使用数组(至少不是内置数组).请改用 std::vector<int>，或者如果您只有一定数量的元素并且想要表达(并且确实需要更好的性能)，请使用 boost::array<int, N>.(甚至是 std::array<int, N>，如果你用 C++11 编程(如果你不知道你是否用 C++11 编程代码>很可能你没有).例如:
If you are new to c++ and get confused about pointers you really don't want to use arrays (at least not builtin arrays). Use std::vector<int> instead, or if you only ever have a certain number of elements and want to express that (and really need the better performance) use boost::array<int, N>.(or even std::array<int, N>, if you program in C++11 (if you don't know whether or not you program in C++11 chances are that you don't).
For example:
std::vector<int> myfunction(const std::vector<int>& my_array) {
std::vector<int> f_array;
for(int i = 0; i < my_array.size(); ++i)
f_array.push_back(my_array[i]);
return f_array;
}
boost::array<int, 2> myfunction(const boost::array<int, 2>& my_array) {
boost::array<int, 2> f_array;
f_array[0] = my_array[0];
f_array[1] = my_array[1];
return f_array;
}
然后您可以使您的复制代码更简单(查找您决定使用的任何类的构造函数和成员函数，以及 STL 算法).示例:
You can then make your copying code simpler (look up the constructors and memberfunctions of whatever class you decide to use, as well as STL algorithms). Example:
std::vector<int> myfunction(const std::vector<int>& my_array) {
std::vector<int> f_array(m_array);
...
return f_array;
}
另外一点，您的代码中有一个错误:您将 my_array 定义为 int my_array[1]，这意味着它是一个包含一个元素的数组，但您可以访问两个元素(my_array[0] 和 my_array[1])，对 my_array[1] 的访问超出范围(intfoo[N] 有 N 个项目的位置，从索引 0 开始，到索引 N-1).我假设你的意思是 int my_array[2].
As another point your code has a bug in it: you define my_array as int my_array[1], meaning its an array with one element, but you access two elements (my_array[0] and my_array[1]), the access to my_array[1] is out of bounds (int foo[N] has place for N items, starting at index 0 and going to index N-1). I assume you really mean int my_array[2].
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