C ++如何获得一个指针数组的长度？ [英] c++ how to get the length of a pointer array?

问题描述

我无法找到一个指针数组的长度。比方说，我有：

I'm having trouble finding the length of an pointer array. Let's say I have:

char array[40] = "hello"; // size 40
int length =  sizeof array / sizeof array[0]; // no problem returns 40

//我如何获取数组的长度只有一个指针数组？

//How do I get the length of the array with only a pointer to the first element in that array?

 char* pchar = array;

//如果

std::strlen(pchar); // this returns the length of 5... i want length 40

//如果

int count = 0;
while(true)
{
  if(*(pchar + count) == '\0') // returns 5...
    break;
   count++;
}

我如何得到它只是从一个指针数组中的第一个元素返回长40？结果
我发现我可以做到这一点。

How do I get it to return length 40 just from a pointer to the first element in the array?
I found that I can do this.

int count = 0;
    while(true)
    {
      if(*(pchar + count) == '\0' && *(pchar + count + 1) != '\0') 
             break;

       count++;
    }

这将返回39，这是件好事，但我觉得这可能是在某些情况下马车。

This returns 39, this is good but I feel like this can be buggy in some situations.

推荐答案

您不能，我害怕。你需要传递数组的人谁需要它的长度。或者，你可以使用的std ::阵列或的std ::矢量或类似的，它保持自身长度的轨道

You can't, I'm afraid. You need to pass the length of the array to anyone who needs it. Or you can use a std::array or std::vector or similar, which keep track of the length themselves.

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