Re: Pointer initialization and usage.

Vickynathan wrote:
> 
> The following code snippet works. I wonder how ? ( this is a code for
> microcontroller )
> 
> void main (void){
> 
> unsigned char xdata * data pwrite;
> unsigned char code *  data pread;
> unsigned char test_array [16];
> unsigned char temp;
> ....
> ....
> ....
> 
> pwrite = (unsigned char xdata *) Scratch_Flash_Addr ;    // I have
> never seen such an initialization ??

You don't show the definition for Scratch_Flash_Addr, but given
your microcontroller comment, I will assume that it's some sort
of #define containing an address, such as:

    #define Scratch_Flash_Addr 0x8004

In order to treat this number as an address, you need to cast it
to a pointer, which is what "(unsigned char xdata *)" does.  It
tells the compiler to treat that number as a pointer to "unsigned
char xdata".  (I am also assuming that "xdata" is some compiler-
specific extension related to this microcontroller.)

> pread = my_array ;
> 
> .....
> .....
> 
> for ( i=0; i< sizeof( my_array); i++ ){
> .....
> temp = pread[i];                         // How is this possible
> without an indirection operator ?

The subscript is the "indirection operator".  Basically, an array
subscript such as "pread[i]" is the same as "*(pread+i)".

> .....
> pwrite[i] = temp;                        // Again no indirection
> operator ??

Ditto.

> .....
> }


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