C-Language const pointer, what is the difference between a const pointer

Read it backwards (as driven by clockwise/spiral Rule) ...

• int*-Pointer to int
• int const *-Pointer to const INT
• int * const-Const pointer to int
• int const * const-const pointer to const INT

Now the first const can is on either side of the type so:

• const int *==int const *
• const int * const==int const * const

If you want to go really crazy you can do things like this:

• int **-pointer to pointer to int
• int ** const-A const pointer to a pointer to an int
• int * const *-A pointer to a const pointer to an int
• int const **-A pointer to a pointer to a const INT
• int * const * const-A const pointer to a const pointer to an int
• ...

And to make sure we is clear on the meaning of const

  const * Foo;int *const Bar //note, you actually need to set the pointer  / /here because you can ' t change it later;)           

foois a variable pointer to a constant int. This is lets you a change, and the value of that. Most often this is seen with cstrings where you have a pointer to a const char . You could change which string of your point to if you can ' t change the content of these strings. This was important when the string itself was in the data segment of a program and shouldn ' t be changed.

baris a const or fixed pointer to a value that can changed. This is a reference without the extra syntactic sugar. Because of this fact, usually your would use a reference where you would use a T* const pointer unless you need to allow null Pointers.

C-Language const pointer, what is the difference between a const pointer