Why is there a cast in this place?

Question

C++ / C#

There is such a record

int a[][3] = {{1, 2, 3},{4, 5, 6}};
  int *b = (int*)a;

Why in the second line (int*)? As I understood this cast. But the letter "a" itself is a pointer. Why bring?

Answer 1

Then that a is int (*)[3], ab is int*