variable declaration

[andrewllewop]

Trying to understand a part of this code:

    

        char   t[4][4], *p = (char *)t;// this line of code I dont understand
        
      

[Chervil]

There are two declarations on that line.

The first is a 2-D array or grid of characters.

    char   t[4][4];

That can be also considered as an array of four character strings.

Then a second declaration is a character pointer char * p, this could point to a character string. It is assigned the value t which will be the address of the start if the 2-D array. But the there is a mismatch. A 2-D array isn't a string, hence the need for the cast (char *) which tells the compiler to convert the value to the required type.

    char * p = (char *) t; // p points to start of array 

Actually, the cast is undesirable, it disguises possible errors. The correct code could look like this, with no cast:

    char * p = t[0]; // p points to first item in the array 

Example:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

#include <iostream> using namespace std; int main() { // Declare array of 4 strings char t[4][4] = { "abc", "123", "xyz", "789" }; // create pointer to first item char * p = t[0]; // output value cout << p << '\n'; }

abc

[andrewllewop]

Ok that makes alot of sense now.
Thank You