Question

Here’s the deal. I have a large character array and am trying to manipulate it. Here’s some code I was using to test the idea:

#include <stdio.h>

char r[65536],*e=r;

main() {
    e+=8;
    while(*e) {
        *e+=1;
        e+=5;
        *e-=1;
        e-=1;
    }
    *e+=1;
    printf("%i",*e);
    printf(" %c",e);
}

What it’s supposed to do is:

1. Set the first element to 8
2. Then, while the current element is not zero,
   1. Move to the next cell
   2. Add 5 to it
   3. Move back
   4. Subtract one. (This repeats 8 times because the while test will fail when it has subtracted the last one)
3. Display the location of the pointer
4. Display the contents of the array that the pointer points to (I hope)

What it does:

1 Φ

as opposed to

40 (   

^^ 8 x 5 = 40, so that’s what it should display.

Any tips/suggestions/criticism accepted.

Answer 1

You’re dereferencing exactly where you should not and vice versa. What you meant to do was:

*e+=8;
while(*e) {
    e+=1;
    *e+=5;
    e-=1;
    *e-=1;
}
*e+=1;
printf("%d",e - r); //index
printf(" %p",e); //pointer value      
printf(" %c",*e); //pointee value

* retrieves the value the pointer points to.