const char triple pointer
===========================

In this section, you are going to learn

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		What is ``const char ***r;`` ?

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		What is ``const char *const **r;`` ?

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		What is ``const char *const *const *r;`` ?

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		What is ``const char *const *const *const r;`` ?

	* Inorder to answer above questions, let us remember a very simple rule

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		Anything after ``const`` keyword CAN NOT be changed

	* Is it that simple ?

		* Yes. Let us see how do we apply above rule to answer the questions

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                Topics in this section,

                        * :ref:`Example 1 : const char ***r; <const_ptr_char_tp_ex_1>`
                        * :ref:`Example 2 : const char *const **r; <const_ptr_char_tp_ex_2>`
                        * :ref:`Example 3 : const char *const *const *r; <const_ptr_char_tp_ex_3>`
                        * :ref:`Example 4 : const char *const *const *const r; <const_ptr_char_tp_ex_4>`
                        * :ref:`Summary <const_ptr_char_tp_ex_5>`

.. _const_ptr_char_tp_ex_1:

.. tab-set::

    .. tab-item:: Example 1 :  const char \*\*\*r;

	* Step 1 : Consider the statement

	.. code-block:: c

		const char ***r;

	* Step 2 : Remove all keywords after ``const``

	.. code-block:: c

		const ***r;

	* Step 3 : Remove everything before ``const``

	.. code-block:: c

		const ***r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const ***r;

	* Step 5 : Now apply the rule. Anything after ``const`` keyword CAN NOT be changed

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		* We see ``***r`` after ``const``
		* Means, ``***r`` CAN NOT be changed again in next line

	* Step 6 : Bonus point ! r, \*r, \*\*r, \*\*\*r are different

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		Means, ``r``, ``*r``, ``**r`` can still be changed

.. _const_ptr_char_tp_ex_2:

.. tab-set::

    .. tab-item:: Example 2 : const char \*const \*\*r;

	* There are two occurences of const keyword

	* Hence, let us apply the same rules two times

.. tab-set::

    .. tab-item:: 2.1 : Rules w.r.t first const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const **r

	* Step 2 : Remove all keywords after first const

	.. code-block:: c

		const ***r

	* Step 3 : Remove everything before first const

	.. code-block:: c

		const ***r

	* Step 4 : Remove assignment

	.. code-block:: c

		const ***r

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*\*\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: 2.2 : Rules w.r.t second const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const **r

	* Step 2 : Remove all keywords after second const

	.. code-block:: c

		const char *const **r

	* Step 3 : Remove everything before second const

	.. code-block:: c

		const **r

	* Step 4 : Remove assignment

	.. code-block:: c

		const **r

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: Summary of Example 2

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		* \*\*\*r, \*\*r CAN NOT be changed
		* \*r, r can be changed 

.. _const_ptr_char_tp_ex_3:

.. tab-set::

    .. tab-item:: Example 3 : const char \*const \*const \*r;

	* There are three occurences of const keyword

	* Hence, let us apply the same rules three times

.. tab-set::

    .. tab-item:: 3.1 : Rules w.r.t first const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *r;

	* Step 2 : Remove all keywords after first const

	.. code-block:: c

		const ***r;

	* Step 3 : Remove everything before first const

	.. code-block:: c

		const ***r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const ***r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*\*\*r CAN NOT be changed
.. tab-set::

    .. tab-item:: 3.2 : Rules w.r.t second const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *r;

	* Step 2 : Remove all keywords after second const

	.. code-block:: c

		const char *const **r;

	* Step 3 : Remove everything before second const

	.. code-block:: c

		const **r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const **r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: 3.3 : Rules w.r.t third const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *r;

	* Step 2 : Remove all keywords after third const

	.. code-block:: c

		const char *const *const *r;

	* Step 3 : Remove everything before third const

	.. code-block:: c

		const *r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const *r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: Summary of Example 3

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		* \*\*\*r, \*\*r, \*r, CAN NOT be changed
		* r can be changed

.. _const_ptr_char_tp_ex_4:

.. tab-set::

    .. tab-item:: Example 4 : const char \*const \*const \*const r;

	* There are Four occurences of const keyword

	* Hence, let us apply the same rules Four times

.. tab-set::

    .. tab-item:: 4.1 : Rules w.r.t first const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *const r;

	* Step 2 : Remove all keywords after first const

	.. code-block:: c

		const ***r;

	* Step 3 : Remove everything before first const

	.. code-block:: c

		const ***r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const ***r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*\*\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: 4.2 : Rules w.r.t second const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *const r;

	* Step 2 : Remove all keywords after second const

	.. code-block:: c

		const char *const **r;

	* Step 3 : Remove everything before second const

	.. code-block:: c

		const **r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const **r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: 4.3 : Rules w.r.t third const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *const r;

	* Step 2 : Remove all keywords after third const

	.. code-block:: c

		const char *const *const *r;

	* Step 3 : Remove everything before third const

	.. code-block:: c

		const *r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const *r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		\*r CAN NOT be changed

.. tab-set::

    .. tab-item:: 4.4 : Rules w.r.t fourth const

	* Step 1 : Consider the statement

	.. code-block:: c

		const char *const *const *const r;

	* Step 2 : Remove all keywords after fourth const

	.. code-block:: c

		const char *const *const *const r;

	* Step 3 : Remove everything before fourth const

	.. code-block:: c

		const r;

	* Step 4 : Remove assignment

	.. code-block:: c

		const r;

	* Step 5 : Now apply the rule. Anything after const keyword CAN NOT be changed

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		r CAN NOT be changed
.. tab-set::

    .. tab-item:: Summary of Example 4

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		\*\*\*r, \*\*r, \*r, r CAN NOT be changed

.. _const_ptr_char_tp_ex_5:

.. tab-set::

    .. tab-item:: Summary

	===================================== ====================================================
	Statement                             Meaning
	===================================== ====================================================
	const char \*\*\*r;	              * ``***r`` CAN NOT be changed again
				              * ``**r`` can be changed again
				              * ``*r`` can be changed again
				              * ``r`` can be changed again
	const char \*const \*\*r;             * ``***r`` CAN NOT be changed again
				              * ``**r`` CAN NOT be changed again
				              * ``*r`` can be changed again
				              * ``r`` can be changed again
	const char \*const \*const \*r;       * ``***r`` CAN NOT be changed again
				              * ``**r`` CAN NOT be changed again
				              * ``*r`` CAN NOT be changed again
				              * ``r`` can be changed again
	const char \*const \*const \*const r; * ``***r`` CAN NOT be changed again
				              * ``**r`` CAN NOT be changed again
				              * ``*r`` CAN NOT be changed again
				              * ``r`` can be changed again
	===================================== ====================================================

.. card:: See Also

        * Current Module

                * :doc:`../const_ptr`

        * Previous Module

                * :doc:`../../memcpy_ptr/memcpy_ptr`

        * Next Module

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        * Other Modules

                * :doc:`../../variable_and_ptr/variable_and_ptr`
                * :doc:`../../array_n_ptrs/array_n_ptrs`
                * :doc:`../../malloc_ptr/malloc_ptr`
                * :doc:`../../typecasting_n_ptr/typecasting_n_ptr`
                * :doc:`../../funcs_n_ptrs/funcs_n_ptrs`
                * :doc:`../../array_of_ptr/array_of_ptr`
                * :doc:`../../ptr_to_array/ptr_to_array`
                * :doc:`../../function_ptr/function_ptr`
                * :doc:`../../pre_incr_ptr/pre_incr_ptr`
                * :doc:`../../post_incr_ptr/post_incr_ptr`
                * :doc:`../../pre_decr_ptr/pre_decr_ptr`
                * :doc:`../../post_decr_ptr/post_decr_ptr`