使用指针获取数组的长度 [英] Get length of an Array using a pointer

问题描述

当我只知道一个指向数组的指针时，有没有办法获取数组的长度?

Is there a way to get the length of an Array when I only know a pointer pointing to the Array?

看下面的例子

int testInt[3];
testInt[0] = 0;
testInt[1] = 1;
testInt[2] = 1;

int* point;
point = testInt;

Serial.println(sizeof(testInt) / sizeof(int)); // returns 3
Serial.println(sizeof(point) / sizeof(int)); // returns 1

(这是来自 Arduino Code 的片段 - 对不起，我不会说"真正的 C).

(This is a snipplet from Arduino Code - I'm sorry, I don't "speak" real C).

推荐答案

简单的答案是不，你不能.您可能希望在内存中保留一个变量，用于存储数组中的项目数量.

The easy answer is no, you cannot. You'll probably want to keep a variable in memory which stores the amount of items in the array.

还有一个不太容易的答案.有一种方法可以确定数组的长度，但为此您必须用另一个元素标记数组的末尾，例如 -1.然后循环遍历它并找到这个元素.这个元素的位置就是长度.但是，这不适用于您当前的代码.

And there's a not-so-easy answer. There's a way to determine the length of an array, but for that you would have to mark the end of the array with another element, such as -1. Then just loop through it and find this element. The position of this element is the length. However, this won't work with your current code.

选择以上之一.

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