String initialization in multidimensional array

Question

How to assign string value in multidimensional array, send the array as a function argument, and return it back to main function? I tried this but it gives an error:

char a[250][250][250];   // does not work
a[][0][2] = "0";         // does not work
a[][1][2] = "0";         // does not work

char a[][2][2] = {"0", "1"};  // works

// error: expected primary-expression before ']' token
a[i][j][max] = add_func(a[i][j][], i, j);

You're confusing characters and strings. Your array is array of chars, not strings. — SomeWittyUsername
– SomeWittyUsername, Commented Dec 30, 2012 at 8:59

Shiplu Mokaddim · Accepted Answer · 2012-12-30 09:35:27Z

7

To initialize character strings table you can use curly braces. And the outer most dimension (I dont know how else can it be called) or the left most number in square is optional.

So this will work

char table[][3][10] = {
    {"row1-col1", "row1-col2", "row1-col3"},
    {"row2-col1", "row2-col2", "row2-col3"},
    {"row3-col1", "row3-col2", "row3-col3"},
    {"row4-col1", "row4-col2", "row4-col3"}
    };

You dont need to type table[4][3][10]. Compiler calculates it. The size of table is 120 bytes. As the contents are all string you can use

char *table[][3] = ...

This will save 20% space.

Curly braces can only be used in initializing phase. Not after that. hence following code will not work.

a[][0][2] = "0";

edited Dec 30, 2012 at 9:35

answered Dec 30, 2012 at 9:28

Shiplu Mokaddim

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1 Comment

WhozCraig Over a year ago

+1, and a mentor long ago called it the "superior" dimension of the array. All others he referred to as "inferior" dimensions. I've also seen them called "dominant" and "sub-dominant".

Community · Accepted Answer · 2017-05-23 12:14:49Z

6

After declaration you can not assign, but use strcpy()

char a[250][250][250];

strcpy(a[0][1],"0");

or assign at the time of declaration:

char a[250][250][250] = {"0","2"};  
char a[][250][250] = {"0","2"};

or if you want to assign a single char.

a[i][j][k] = '0';

Where i, j, k are any value less than 250

How to Declaration and Initialization 3D Array IN C

In-general a[3][4][2] is a three-dimension array, that can be view as

a[3][4][2] : Consist of 3 two-dimension arrays, where each 2-D array are consist of 4-rows and 2-colunms. can be declare as:

char a[3][4][2] =  { 
                       { //oth 2-D array 
                         {"0"},
                         {"1"},
                         {"2"},
                         {"4"}
                       },
                       { //1th 2-D Array
                         {"0"},
                         {"1"},
                         {"2"},
                         {"4"}
                       },
                       { //2nd 2-D array
                         {"0"},
                         {"1"},
                         {"2"},
                         {"4"}
                       },
                   };

Note: "1" means two chars, one additional fro null ('\0') char.

If integer array:

int a[3][2][3]=  
        {
            { //oth 2-D array, consists of 2-rows and 3-cols
            {11, 12, 13},
            {17, 18, 19}
            },
            {//1th 2-D array, consists of 2-rows and 3-cols
            {21, 22, 23},
            {27, 28, 29}
            },
            {//2th 2-D array, consists of 2-rows and 3-cols
            {31, 32, 33},
            {37, 38, 39}
            },
        };

Link to understand

Second error:

to this a[i][j][max] a char can assign not string so,

a[i][j][max] = '0' ; // is correct  expression

but

a[i][j][max] = "0";  // is not correct, wrong

Please read WhozCraig comment. you are declaring huge memory in stack!

According to your comment :

function declaration:

char add_func(char a[250][250][250], int i, int j); // function definition

try like this:

  char a[250][250][250];
  a[i][j][max] = add_func(a, i, j );

edited May 23, 2017 at 12:14

CommunityBot

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answered Dec 30, 2012 at 8:58

Grijesh Chauhan

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7 Comments

Grijesh Chauhan Over a year ago

@sabbir_pstu : Which passing to a function ?

sabbir Over a year ago

the present value of a[][][] will be passed to function as function parameter and return other multidimensional array variable.

Grijesh Chauhan Over a year ago

@sabbir_pstu ok I guess it should be like add_func( a, i, j ); can't assign to a[i][j][max]

Grijesh Chauhan Over a year ago

@sabbir_pstu: you need to show definition of add_func, then I can help you.

sabbir Over a year ago

char add_func(char a[250][250][250], int i, int j); // function defination

|

CubeSchrauber · Accepted Answer · 2012-12-30 09:05:13Z

2

You probably would like to use pointers instead:

char *a[2][2] = { "0", "1", "2", "3" };

answered Dec 30, 2012 at 9:05

CubeSchrauber

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2 Comments

Mats Petersson Over a year ago

Assuming each entry isn't going to be altered, that will work.

CubeSchrauber Over a year ago

Definitely true. But you still can assign individual strings by constructs like a[i][j] = "something" or a[i][j] = strdup(something).

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