多维数组和指向指针值的指针

Question

Given the following:

int ar2[3][2];
int * pt;
int **p2;
p2 = &pt;
*p2 = ar2[0];

This is what my book says:

*p2 is type pointer-to-int, making it compatible with ar2[0]. Recall that ar2[0] is a pointer to its first element , art2[0][0], making ar2[0] type pointer-to-int also.

Is it everything true?

Answer 1

Yes.

*p2 is type pointer-to-int, making it compatible with ar2[0].

To make this easier to see, ar2 can be seen as a pointer to an array, being that array ar2[0]. Then, ar2+1 would be a pointer to ar2[1], and ar2+2 a pointer to ar2[2].

So, you could define int (* arp)[2] = ar2 , making explicit your reinterpretation of ar2 as a pointer to an array.

Recall that ar2[0] is a pointer to its first element, art2[0][0], making ar2[0] type pointer-to-int also.

Then, ar2[0]+1 would be a pointer to ar2[0][1].

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This way, you can always reinterpret an array as a pointer to the first element of it, being it an integer, an array or even another pointer.

For instance, int * par[3] would be an array of 3 pointers, OR a pointer to the first of the 3 pointers ( par would be int ** and par[0] int * ).