Basics of Integer Triple Pointers
=====================================

In this section, you are going to learn

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                How to use Triple Pointers ?

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                Basics of Triple Pointers

                * :ref:`1 Triple Pointer 1 Double Pointer, 1 Single Pointer : Simple variables <basic_ptr_int_tp_sp_ex1>`
                * :ref:`1 Triple Pointer, 1 Double Pointer, 1 Single Pointer : With Single pointer pointing to arrays <basic_ptr_int_tp_sp_ex2>`
                * :ref:`1 Triple Pointer, 1 Double Pointer, 1 Single Pointer : With Single pointer heap allocation <basic_ptr_int_tp_sp_ex3>`
                * :ref:`1 Triple Pointer, 1 Double Pointer : With two heap allocations : Create 1x1 array <basic_ptr_int_tp_sp_ex4>`
                * :ref:`1 Triple Pointer, 1 Double Pointer : With two heap allocations : Create 1x10 array <basic_ptr_int_tp_sp_ex5>`
                * :ref:`1 Triple Pointer, 1 Double Pointer : Double Pointer Pointing to array of single pointers : Static <basic_ptr_int_tp_sp_ex6>`
                * :ref:`1 Triple Pointer, 1 Double Pointer : Pointing to array of single pointers : Dynamic <basic_ptr_int_tp_sp_ex7>`

.. _basic_ptr_int_tp_sp_ex1:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer, 1 Single Pointer : Simple variables

                * Step 1 : Define a Integer

                .. code-block:: c

                        int c = 65;

                * Step 2 : Define a Single pointer

                .. code-block:: c

                        int *sp = &c;

                OR

                .. code-block:: c

                        int *sp;

                        sp = &c;

                * Step 3 : Define a Double pointer

                .. code-block:: c

                        int **dp = &sp;

                OR

                .. code-block:: c

                        int **dp;

                        dp = &sp;

                * Step 4 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 5 : Access user data (in this case integer) using single pointer

                .. code-block:: c

                        printf("*sp = %d\n", *sp);

                * Step 6 : Access user data (in this case integer) using double pointer

                .. code-block:: c

                        printf("**dp = %d\n", **dp);

                * Step 7 : Access user data (in this case integer) using triple pointer

                .. code-block:: c

                        printf("***tp = %d\n", ***tp);

                * Step 8 : Use \*\*tp to point to new user data (in this case variable d)

                .. code-block:: c

                        **tp = &d;

                * Step 9 : Now user data can be accessed using \*sp, \*\*dp, \*\*\*tp which prints value of integer d

                .. code-block:: c

                        printf("d = %d\n", d);
                        printf("d = %d\n", *sp);
                        printf("d = %d\n", **dp);
                        printf("d = %d\n", ***tp);

                * See full program below

                .. code-block:: c

                        #include <stdio.h>

                        int main(void)
                        {
                                int c = 65;
                                int *sp = &c;
                                int **dp = &sp;
                                int ***tp = &dp;

                                printf("c = %d\n", c);
                                printf("*sp = %d\n", *sp);
                                printf("**dp = %d\n", **dp);
                                printf("***tp = %d\n", ***tp);

                                int d = 100;

                                **tp = &d;

                                printf("d = %d\n", d);
                                printf("*sp = %d\n", *sp);
                                printf("**dp = %d\n", **dp);
                                printf("***tp = %d\n", ***tp);

                                return 0;
                        }

                * Output is as below

                .. code-block:: c

                        c = 65
                        *sp = 65
                        **dp = 65
                        ***tp = 65

                        d = 100
                        *sp = 100
                        **dp = 100
                        ***tp = 100

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                        Summary of Naming conventions

                        Consider

                        .. code-block:: c

                                int ***tp;

                        then

                        * tp is a triple pointer
                        * \*tp is a double pointer
                        * \*\*tp is a single pointer
                        * \*\*\*tp is user data

.. _basic_ptr_int_tp_sp_ex2:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer, 1 Single Pointer : With Single pointer pointing to arrays

                * Step 1 : Define a single dimension array of integers

                .. code-block:: c

                        int arr[5] = {1, 2, 3, 4, 5};

                * Step 2 : Define a single pointer

                .. code-block:: c

                        int *sp = arr;

                OR

                .. code-block:: c

                        int *sp;

                        sp = arr;

                OR

                .. code-block:: c

                        int *sp;

                        sp = &arr[0];

                * Step 3 : Define a double pointer

                .. code-block:: c

                        int **dp = &sp;

                OR

                .. code-block:: c

                        int **dp;

                        dp = &sp;

                * Step 4 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 5 : Access user data (in this case array of integers) using single pointer variable ``arr``

                .. code-block:: c

                        for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                        {
                                printf("arr[%d] = %d\n", i, arr[i]);
                        }

                * Step 5 : Access user data (in this case array of integers) using single pointer variable ``sp``

                .. code-block:: c

                        for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                        {
                                printf("sp[%d] = %d\n", i, sp[i]);
                        }


                * Step 6 : Access user data (in this case array of integers) using double pointer variable ``dp``

                .. code-block:: c

                        for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                        {
                                printf("(*dp)[%d] = %d\n", i, (*dp)[i]);
                        }

                * Step 7 : Access user data (in this case array of integers) using triple pointer variable ``tp``

                .. code-block:: c

                        for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                        {
                                printf("(**tp)[%d] = %d\n", i, (**tp)[i]);
                        }

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                        Note ``*dp`` should be called as single pointer because of below equations

                        * dp = &sp;
                        * \*dp = sp;

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                        Note ``**tp`` should be called as single pointer because of below equations

                        * tp = &dp;
                        * \*tp = dp;
                        * \*tp = &sp;
                        * \*\*tp = sp;  

                * See full program below

                .. code-block:: c

                        #include <stdio.h>

                        int main(void)
                        {
                                int arr[5] = {1, 2, 3, 4, 5};
                                int *sp = arr;
                                int **dp = &sp;
                                int ***tp = &dp;

                                for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                                {
                                        printf("arr[%d] = %d\n", i, arr[i]);
                                }

                                for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                                {
                                        printf("sp[%d] = %d\n", i, sp[i]);
                                }

                                for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                                {
                                        printf("(*dp)[%d] = %d\n", i, (*dp)[i]);
                                }

                                for (int i = 0 ; i < sizeof(arr)/sizeof(arr[0]); i++)
                                {
                                        printf("(**tp)[%d] = %d\n", i, (**tp)[i]);
                                }

                                return 0;
                        }

                * Output is as below

                .. code-block:: c

                        arr[0] = 1
                        arr[1] = 2
                        arr[2] = 3
                        arr[3] = 4
                        arr[4] = 5

                        sp[0] = 1
                        sp[1] = 2
                        sp[2] = 3
                        sp[3] = 4
                        sp[4] = 5

                        (*dp)[0] = 1
                        (*dp)[1] = 2
                        (*dp)[2] = 3
                        (*dp)[3] = 4
                        (*dp)[4] = 5

                        (**tp)[0] = 1
                        (**tp)[1] = 2
                        (**tp)[2] = 3
                        (**tp)[3] = 4
                        (**tp)[4] = 5

.. _basic_ptr_int_tp_sp_ex3:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer, 1 Single Pointer : With Single pointer heap allocation

                * Step 1 : Define a single pointer

                .. code-block:: c

                        int *sp;

                * Step 2 : Allocate heap memory to single pointer

                .. code-block:: c

                        sp = malloc(5 * sizeof(int));

                * Step 3 : Copy User data to heap memory

                .. code-block:: c

                        sp[0] = 100;
                        sp[1] = 200;
                        sp[2] = 300;
                        sp[3] = 400;
                        sp[4] = 500;

                * Step 4 : Define a double pointer

                .. code-block:: c

                        int **dp;
                        dp = &sp;

                * Step 5 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 6 : Access User data using single pointer variable ``sp``

                .. code-block:: c

                        printf("sp[3] = %c\n", sp[3]);

                * Step 7 : Access User data using double pointer variable ``dp``

                .. code-block:: c

                        printf("(*dp)[3] = %c\n", (*dp)[3]);

                * Step 8 : Access User data using triple pointer variable ``tp``

                .. code-block:: c

                        printf("(**tp)[3] = %c\n", (**tp)[3]);

                * Step 9 : Free memory after usage

                .. code-block:: c

                        free(sp);

                OR

                .. code-block:: c

                        free(*dp);

                OR

                .. code-block:: c

                        free(**tp);

                * See full program below

                .. code-block:: c

                        #include <stdio.h>
                        #include <stdlib.h>
                        #include <string.h>

                        int main(void)
                        {
                                int *sp;

                                sp = malloc(5 * sizeof(int));

                                sp[0] = 100;
                                sp[1] = 200;
                                sp[2] = 300;
                                sp[3] = 400;
                                sp[4] = 500;

                                int **dp;
                                dp = &sp;

                                int ***tp;
                                tp = &dp;

                                //Access individual integer using "sp"
                                printf("sp[3] = %d\n", sp[3]);

                                //Access individual integer using "dp"
                                printf("(*dp)[3] = %d\n", (*dp)[3]);

                                //Access individual integer using "tp"
                                printf("(**tp)[3] = %d\n", (**tp)[3]);

                                // Access user data (in this case array of integers) using single pointer variable ``sp``
                                for (int i = 0 ; i < 5; i++)
                                {
                                        printf("sp[%d] = %d\n", i, sp[i]);
                                }

                                // Access user data (in this case array of integers) using double pointer variable ``dp``
                                for (int i = 0 ; i < 5; i++)
                                {
                                        printf("(*dp)[%d] = %d\n", i, (*dp)[i]);
                                }

                                // Access user data (in this case array of integers) using double pointer variable ``tp``
                                for (int i = 0 ; i < 5; i++)
                                {
                                        printf("(**tp)[%d] = %d\n", i, (**tp)[i]);
                                }

                                free(sp);

                                return 0;
                        }

                * Output is as below

                .. code-block:: c

                        sp[3] = 400
                        (*dp)[3] = 400
                        (**tp)[3] = 400

                        sp[0] = 100
                        sp[1] = 200
                        sp[2] = 300
                        sp[3] = 400
                        sp[4] = 500

                        (*dp)[0] = 100
                        (*dp)[1] = 200
                        (*dp)[2] = 300
                        (*dp)[3] = 400
                        (*dp)[4] = 500

                        (**tp)[0] = 100
                        (**tp)[1] = 200
                        (**tp)[2] = 300
                        (**tp)[3] = 400
                        (**tp)[4] = 500

.. _basic_ptr_int_tp_sp_ex4:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer : With two heap allocations : Create 1x1 array

                * Step 1 : Define a double pointer

                .. code-block:: c

                        int **dp;

                * Step 2 : Allocate memory to a double pointer

                .. code-block:: c

                        dp = malloc(sizeof(int *));

                * Step 3 : Allocate memory to a single pointer

                .. code-block:: c

                        *dp = malloc(sizeof(int));

                * Step 4 : Store user data

                .. code-block:: c

                        **dp = 65;

                * Step 5 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 6 : Read user data using ``dp``

                .. code-block:: c

                        printf("**dp = %d\n", **dp);

                * Step 7 : Read user data using ``tp``

                .. code-block:: c

                        printf("***tp = %d\n", ***tp);

                * Step 8 : Free memory in opposite flow of allocation

                .. code-block:: c

                        free(*dp);

                        free(dp);

                OR

                .. code-block:: c

                        free(**tp);

                        free(*tp);

                * See full program below

                .. code-block:: c

                        #include <stdio.h>
                        #include <string.h>
                        #include <stdlib.h>

                        int main(void)
                        {
                                int **dp;

                                dp = malloc(sizeof(int *));

                                *dp = malloc(sizeof(int));

                                **dp = 65;

                                int ***tp;
                                tp = &dp;

                                printf("**dp = %d\n", **dp);

                                printf("***tp = %d\n", ***tp);

                                free(*dp); // or free(**tp);

                                free(dp);  // or free(*tp);

                                return 0;
                        }

                * Output is as below

                .. code-block:: c

                        **dp  = 65
                        ***tp = 65

.. _basic_ptr_int_tp_sp_ex5:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer : With two heap allocations : Create 1x10 array

                * Step 1 : Define a double pointer

                .. code-block:: c

                        int **dp;

                * Step 2 : Allocate memory to a double pointer

                .. code-block:: c

                        dp = malloc(sizeof(int *));

                * Step 3 : Allocate memory to a single pointer

                .. code-block:: c

                        *dp = malloc(5 * sizeof(int));

                * Step 4 : Copy User data to heap

                .. code-block:: c

                        (*dp)[0] = 100;
                        (*dp)[1] = 200;
                        (*dp)[2] = 300;
                        (*dp)[3] = 400;
                        (*dp)[4] = 500;

                * Step 5 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 6 : Read user data from heap using ``dp``

                .. code-block:: c

                        for (int i = 0; i < 5; i++) {
                                printf("(*dp)[%d] = %d\n", i, (*dp)[i]);
                        }

                * Step 7 : Read user data from heap using ``tp``

                .. code-block:: c

                        for (int i = 0; i < 5; i++) {
                                printf("(**tp)[%d] = %d\n", i, (**tp)[i]);
                        }

                * Step 6 : Free memory in opposite flow of allocation

                .. code-block:: c

                        free(*dp);

                        free(dp);

                OR

                .. code-block:: c

                        free(**tp);

                        free(*tp);

                * See full program below

                .. code-block:: c
        
                        #include <stdio.h>
                        #include <string.h>
                        #include <stdlib.h>

                        int main(void)
                        {
                                int **dp;

                                dp = malloc(sizeof(int *));

                                *dp = malloc(5 * sizeof(int));
                                memset(*dp, 0, 5 * sizeof(int));

                                (*dp)[0] = 100;
                                (*dp)[1] = 200;
                                (*dp)[2] = 300;
                                (*dp)[3] = 400;
                                (*dp)[4] = 500;

                                int ***tp;
                                tp = &dp;

                                for (int i = 0; i < 5; i++) {
                                        printf("(*dp)[%d] = %d\n", i, (*dp)[i]);
                                }

                                for (int i = 0; i < 5; i++) {
                                        printf("(**tp)[%d] = %d\n", i, (**tp)[i]);
                                }

                                free(*dp); // or free(**tp);

                                free(dp);  // or free(*tp);

                                return 0;
                        }

                * Output is as below

                .. code-block:: c

                        (*dp)[0] = 100
                        (*dp)[1] = 200
                        (*dp)[2] = 300
                        (*dp)[3] = 400
                        (*dp)[4] = 500

                        (**tp)[0] = 100
                        (**tp)[1] = 200
                        (**tp)[2] = 300
                        (**tp)[3] = 400
                        (**tp)[4] = 500

.. _basic_ptr_int_tp_sp_ex6:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer : Double Pointer Pointing to array of single pointers : Static

                * Step 1 : Define 3 Single dimension integer arrays

                .. code-block:: c

                        int arr0[5] = {1, 2, 3, 4, 5};
                        int arr1[5] = {10, 20, 30, 40, 50};
                        int arr2[5] = {100, 200, 300, 400, 500};

                * Step 2 : Define array of single pointers

                .. code-block:: c

                        int *sp_arr[] = {arr0, arr1, arr2};

                * Step 3 : Define a double pointer

                .. code-block:: c

                        int **dp;

                        dp = sp_arr;

                * Step 4 : Use ``dp`` to change contents of single dimension arrays

                .. code-block:: c


                * Step 5 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 6 : Use ``sp_arr`` to access contents of single dimension arrays

                .. code-block:: c

                        sp_arr[0][2] = 9;   // Same as arr0[2]
                        sp_arr[1][2] = 99;  // Same as arr1[2]
                        sp_arr[2][2] = 999; // Same as arr2[2]

                        for (int i = 0; i < 3; i++)
                        {
                                for (int j = 0; j < 5; j++)
                                {
                                        printf("sp_arr[%d][%d] = %d\n", i, j, sp_arr[i][j]);
                                }
                                printf("\n");
                        }

                * Step 7 : Use ``dp`` to access contents of single dimension arrays

                .. code-block:: c

                        dp[0][2] = 9;   // Same as arr0[2]
                        dp[1][2] = 99;  // Same as arr1[2]
                        dp[2][2] = 999; // Same as arr2[2]

                        printf("------------ Access arrays using dp -----------\n");
                        for (int i = 0; i < 3; i++)
                        {
                                for (int j = 0; j < 5; j++)
                                {
                                        printf("dp[%d][%d] = %d\n", i, j, dp[i][j]);
                                }
                                printf("\n");
                        }

                * Step 8 : Use ``tp`` to access contents of single dimension arrays

                .. code-block:: c

                        (*tp)[0][2] = 9;   // Same as arr0[2]
                        (*tp)[1][2] = 99;  // Same as arr1[2]
                        (*tp)[2][2] = 999; // Same as arr2[2]

                        for (int i = 0; i < 3; i++)
                        {
                                for (int j = 0; j < 5; j++)
                                {
                                        printf("(*tp)[%d][%d] = %d\n", i, j, (*tp)[i][j]);
                                }
                                printf("\n");
                        }

                * See full program below

                .. code-block:: c

                        #include <stdio.h>
                        #include <stdlib.h>
                        #include <string.h>

                        int main(void)
                        {
                                int arr0[5] = {1, 2, 3, 4, 5};
                                int arr1[5] = {10, 20, 30, 40, 50};
                                int arr2[5] = {100, 200, 300, 400, 500};

                                int *sp_arr[] = {arr0, arr1, arr2};

                                // Use ``sp_arr`` to change contents of single dimension arrays
                                sp_arr[0][2] = 9;   // Same as arr0[2]
                                sp_arr[1][2] = 99;  // Same as arr1[2]
                                sp_arr[2][2] = 999; // Same as arr2[2]

                                // Use ``sp_arr`` to access contents of single dimension arrays
                                printf("------------ Access arrays using sp_arr -----------\n");
                                for (int i = 0; i < 3; i++)
                                {
                                        for (int j = 0; j < 5; j++)
                                        {
                                                printf("sp_arr[%d][%d] = %d\n", i, j, sp_arr[i][j]);
                                        }
                                        printf("\n");
                                }

                                int **dp;

                                dp = sp_arr;

                                // Use ``dp`` to change contents of single dimension arrays
                                dp[0][2] = 9;   // Same as arr0[2]
                                dp[1][2] = 99;  // Same as arr1[2]
                                dp[2][2] = 999; // Same as arr2[2]

                                // Use ``dp`` to access contents of single dimension arrays
                                printf("------------ Access arrays using dp -----------\n");
                                for (int i = 0; i < 3; i++)
                                {
                                        for (int j = 0; j < 5; j++)
                                        {
                                                printf("dp[%d][%d] = %d\n", i, j, dp[i][j]);
                                        }
                                        printf("\n");
                                }

                                int ***tp;

                                tp = &dp;
        
                                // Use ``tp`` to change contents of single dimension arrays
                                (*tp)[0][2] = 9;   // Same as arr0[2]
                                (*tp)[1][2] = 99;  // Same as arr1[2]
                                (*tp)[2][2] = 999; // Same as arr2[2]

                                // Use ``tp`` to access contents of single dimension arrays
                                printf("------------ Access arrays using tp -----------\n");
                                for (int i = 0; i < 3; i++)
                                {
                                        for (int j = 0; j < 5; j++)
                                        {
                                                printf("(*tp)[%d][%d] = %d\n", i, j, (*tp)[i][j]);
                                        }
                                        printf("\n");
                                }

                                return 0;
                        }
                        
                * Output is as below

                .. code-block:: c

                        ------------ Access arrays using sp_arr -----------
                        sp_arr[0][0] = 1
                        sp_arr[0][1] = 2
                        sp_arr[0][2] = 9
                        sp_arr[0][3] = 4
                        sp_arr[0][4] = 5

                        sp_arr[1][0] = 10
                        sp_arr[1][1] = 20
                        sp_arr[1][2] = 99
                        sp_arr[1][3] = 40
                        sp_arr[1][4] = 50

                        sp_arr[2][0] = 100
                        sp_arr[2][1] = 200
                        sp_arr[2][2] = 999
                        sp_arr[2][3] = 400
                        sp_arr[2][4] = 500

                        ------------ Access arrays using dp -----------
                        dp[0][0] = 1
                        dp[0][1] = 2
                        dp[0][2] = 9
                        dp[0][3] = 4
                        dp[0][4] = 5

                        dp[1][0] = 10
                        dp[1][1] = 20
                        dp[1][2] = 99
                        dp[1][3] = 40
                        dp[1][4] = 50

                        dp[2][0] = 100
                        dp[2][1] = 200
                        dp[2][2] = 999
                        dp[2][3] = 400
                        dp[2][4] = 500

                        ------------ Access arrays using tp -----------
                        (*tp)[0][0] = 1
                        (*tp)[0][1] = 2
                        (*tp)[0][2] = 9
                        (*tp)[0][3] = 4
                        (*tp)[0][4] = 5

                        (*tp)[1][0] = 10
                        (*tp)[1][1] = 20
                        (*tp)[1][2] = 99
                        (*tp)[1][3] = 40
                        (*tp)[1][4] = 50

                        (*tp)[2][0] = 100
                        (*tp)[2][1] = 200
                        (*tp)[2][2] = 999
                        (*tp)[2][3] = 400
                        (*tp)[2][4] = 500

.. _basic_ptr_int_tp_sp_ex7:

.. tab-set::

        .. tab-item:: 1 Triple Pointer, 1 Double Pointer : Pointing to array of single pointers : Dynamic

                * Step 1 : Define a double pointer

                .. code-block:: c

                        int **dp;

                * Step 2 : Allocate heap memory : Create 2 single pointers ``dp[0]``, ``dp[1]``

                .. code-block:: c

                        dp = malloc(2 * sizeof(int *));

                * Step 3 : Allocate heap memory : Create 2 single dimension integer arrays of size 3 integers each

                .. code-block:: c

                        dp[0] = malloc(3 * sizeof(int));
                        dp[1] = malloc(3 * sizeof(int));

                * Step 4 : Store user data

                .. code-block:: c

                        dp[0][0] = 1; dp[0][1] = 2; dp[0][2] = 3;
                        dp[1][0] = 10; dp[1][1] = 20; dp[1][2] = 30;

                * Step 5 : Define a Triple pointer

                .. code-block:: c

                        int ***tp = &dp;

                OR

                .. code-block:: c

                        int ***tp;

                        tp = &dp;

                * Step 6 : Access user data using ``dp``

                .. code-block:: c

                        for (int i = 0 ; i < 2; i++)
                        {
                                for (int j = 0; j < 3; j++)
                                {
                                        printf("dp[%d][%d] = %d\n", i, j, dp[i][j]);
                                }
                        }

                * Step 7 : Access user data using ``tp``

                .. code-block:: c

                        for (int i = 0 ; i < 2; i++)
                        {
                                for (int j = 0; j < 3; j++)
                                {
                                        printf("(*tp)[%d][%d] = %d\n", i, j, (*tp)[i][j]);
                                }
                        }

                * Step 6 : Free 2 integer arrays

                .. code-block:: c

                        free(dp[0]);
                        free(dp[1]);

                OR                        

                .. code-block:: c

                        free((*tp)[0]);
                        free((*tp)[1]);

                * Step 7 : Free 2 single pointers

                .. code-block:: c

                        free(dp);

                * See full program below

                .. code-block:: c

                        #include <stdio.h>
                        #include <stdlib.h>
                        #include <string.h>

                        int main(void)
                        {
                                int **dp;

                                dp = malloc(2 * sizeof(int *));
                                dp[0] = malloc(3 * sizeof(int));
                                dp[1] = malloc(3 * sizeof(int));

                                // Store user data using ``dp``
                                dp[0][0] = 1; dp[0][1] = 2; dp[0][2] = 3;
                                dp[1][0] = 10; dp[1][1] = 20; dp[1][2] = 30;

                                // Access user data using ``dp``
                                for (int i = 0 ; i < 2; i++)
                                {
                                        for (int j = 0; j < 3; j++)
                                        {
                                                printf("dp[%d][%d] = %d\n", i, j, dp[i][j]);
                                        }
                                }

                                int ***tp;

                                tp = &dp;

                                // Access user data using ``tp``
                                for (int i = 0 ; i < 2; i++)
                                {
                                        for (int j = 0; j < 3; j++)
                                        {
                                                printf("(*tp)[%d][%d] = %d\n", i, j, (*tp)[i][j]);
                                        }
                                }

                                free(dp[0]);
                                free(dp[1]);

                                free(dp);

                                return 0;
                        }

                * Output as is below

                .. code-block:: c

                        dp[0][0] = 1
                        dp[0][1] = 2
                        dp[0][2] = 3
                        dp[1][0] = 10
                        dp[1][1] = 20
                        dp[1][2] = 30

                        (*tp)[0][0] = 1
                        (*tp)[0][1] = 2
                        (*tp)[0][2] = 3
                        (*tp)[1][0] = 10
                        (*tp)[1][1] = 20
                        (*tp)[1][2] = 30

.. card:: See Also

        * Current Module

                * :doc:`../basic_ptr`

        * Previous Module

                * :doc:`../../variable_and_ptr/variable_and_ptr`

        * Next Module

                * :doc:`../../array_n_ptrs/array_n_ptrs`

        * Other Modules

                * :doc:`../../malloc_ptr/malloc_ptr`
                * :doc:`../../typecasting_n_ptr/typecasting_n_ptr`
                * :doc:`../../funcs_n_ptrs/funcs_n_ptrs`
                * :doc:`../../memcpy_ptr/memcpy_ptr`
                * :doc:`../../const_ptr/const_ptr`
                * :doc:`../../void_ptr/void_ptr`
                * :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`