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Retrocomputing

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    Unless someone can dig up sources from interviews etc., the answer will probably remain opinion-based and speculation, but data structures were a hot topic in other languages at that time (Algol), and those languages did distinguish between pointers and arrays. IIRC it also makes a difference for lvalues vs. rvalues (but I would have to look this up). Commented yesterday
  • 2
    " 0[ptr] == ptr[0] == *ptr " -- this part is actually pretty true (the same or equivalent) in C. Because a[b] is effectively *(a+b), thus no difference between a[b] and b[a]. Commented 20 hours ago
  • It depends on the types of a and b, but as long as one is an integer and the other a pointer, you're fine. a[b] is equivalent to the expression *((a) + (b)). Adding an integer to a pointer gives an address depending on the pointer type, regardless of whether the integer or the pointer comes first. Adding two pointers isn't allowed. Commented 17 hours ago
  • Before addition, integer is multipied by the size of object which the pointer is typed with. Therefore, *(ptr+index) is always fine, the same as ptr[index] or index[ptr]. Commented 16 hours ago
  • Note that BCPL had neither have data-structures nor pointers as in C , instead it had word-pointers (to the pain of Amiga users) so for 32-bit words and 8-bit bytes it means that all pointers were divided by 4. Since C improved that part could that be linked with the syntax change (either because some version had both and needed different syntax, or just to avoid confusion)? Commented 16 hours ago