指针数组的长度。

if I have an array of pointers like char **lines, how can i determine its length? Thanks

如果我有一个指针数组，比如char **lines，我如何确定它的长度?谢谢

5 个解决方案

#1

You can't. You have to manually keep track of the length of arrays.

你不能。您必须手动跟踪数组的长度。

#2

You can't reliably.

你不能可靠地。

Sometimes, there is a null pointer marking the end - it is one convention sometimes used. More often, you need to be told the length.

有时，有一个空指针标记结束——这是一种有时使用的约定。更多时候，你需要被告知长度。

But there is no fool-proof way of determining the length. You have to know (or be told) the length, somehow.

但是没有万无一失的方法来确定长度。你必须知道(或被告知)长度。

#3

That's not an array of pointers, it's a pointer to a pointer.

它不是指针数组，而是指向指针的指针。

#4

It depends on the data. If there is no associated count, it could be a NULL terminated list.

这取决于数据。如果没有关联的计数，它可以是一个空终止列表。

char** lines = mysteryfunction();
for ( ;*lines;lines++ ) { 
    printf( "%s\n", *list ); 
}

#5

Getting the length of a pointer to an array

char *array[]={"welcome","to","India"};

length=sizeof(array)/sizeof(array[0]);

Output:

输出:

3

3

we can get the length by dividing (size of pointer to array by size of single one)

我们可以通过划分(大小为单个的数组的指针大小)来获得长度

Because there is no predefined function for getting length of array..

因为没有预定义的函数来获取数组的长度。