I found the following declaration in my c Book, can anyone explain it:
char *dic[][40]={
"atlas", "A volume of maps",
"car", "a vehicle",
"telephone", "a communication device",
"", ""
}
Here what does the 40 means i.e. which dimension this is?
This is actually kind of a weird way to initialize the dictionary.
It is a 2D array of char* (zero terminated (\0) strings).
The dimensions are [rows][columns].
So you have 1 row (determined by the initializer) and 40 columns of strings,
where 8 of them are initialized.
NOTE: Are you sure it isnt char dic[][40] (i.e., a list of strings of max-length 40) ?
dic is a two-dimensional array of char*; its dimensions are 1 x 40.
The 40 is given in the declarator and the 1 is implied by the fact that there is only one array in the initializer. The full initializer would have another set of braces, e.g.,
char *dic[][40] =
{
{
"atlas", "A volume of maps",
"car", "a vehicle",
"telephone", "a communication device",
"", ""
}
};
With the extra braces, it is clearer that the implicit dimension is 1.
Each element in the two-dimensional array is a pointer of type char*. The first eight pointers are initialized to point to the eight string literals given in the initializer.
I think that there may be error in book, it seems that they wanted dictionary - 3D array:
char *dic[][40]={
{"atlas", "A volume of maps"},
{"car", "a vehicle"},
{"telephone", "a communication device"},
{"", ""}
};
The 40 in your code means the maximum length of characters (or the total length of the string) is 40.
Think char *dic[][40] as an array of pointers. Wherein one pointer points to a maximum of 40 characters.
char dic[][40], this is actually a list of 40 strings.