3D Array of _unequal numbers_ of strings

Question

I realise this has probably been done before but searching has turned up blank for this specific wrinkle.

If we want to define an array containing some strings, we can do:

char *strings[] = {"one","two","three"};

And if we want to define an array of arrays of strings, we can do:

char *strings[][] =
{
  {"one","two","three"},
  {"first","second","third"},
  {"ten","twenty","thirty"}
};

But I can't seem to do this:

char *strings[][] =
{
  {"one","two"},
  {"first","second","third","fourth","fifth"},
  {"ten","twenty","thirty"}
};

Doing that throws compiler errors.

(Examples from string initialization in multidimensional array)

error: array type has incomplete element type and warning: braces around scalar initializer — John U, Jun 11 '13 at 14:23
http://stackoverflow.com/questions/1083658/jagged-array-in-c — Suvarna Pattayil, Jun 11 '13 at 14:28

score 2 · Accepted Answer · edited May 23 '17 at 12:28

From here,

char *strings[][]

strings is a 2D array.

Incase of,

char *strings[][] =
{
  {"one","two","three"},
  {"first","second","third"},
  {"ten","twenty","thirty"}
};

The compiler automatically determines the no of columns in strings. In this case each strings[i] is a row in the 2D array. Also, its a pointer (array names are pointers) of type char (*string)[3] i.e. to char array of sixe 3.

char *strings[][] =
{
  {"one","two"},
  {"first","second","third","fourth","fifth"},
  {"ten","twenty","thirty"}
};

In this case, the compiler can't create an array (the array has to have elements of same type) because strings[0] would be of type char (*strings)[2], strings[1] would be of type char (*strings)[5] and strings[2] would be of type char (*strings)[3]

Hence, the compiler says incomplete element type.

You need to specify the number of columns (N) at declaration(which will make each row of type char (*string)[N]) or assign dynamically.

3D Array of _unequal numbers_ of strings

1 Answers1