array-subscript-operator [] 有

The array-subscript-operator [] has higher precedence then the dereferencing operator *.

所以您要更改

*a[3] = ...

成为

(*a)[3] = ...

与 b 相同。

已将编译器的警告级别设置得足够高，它应该已经对此发出警告。或至少告诉过您，它们是带有

Having set the compiler's warning level high enough, it should have warned you about this. Or at least told you that their is something fishy with

*a[3] = '\0';