Access to Fields of Records

Fields of a record are accessed by specifying a pointer to the record, an operator for dereferencing the pointer (i.e., changing from the pointer to what it points to), and the name of the field.

Scheme (cdr p)
Pascal p^.cdr
C++ p->cdr
Java p.cdr

long length (cons *l)    (define (length2 l)
    long n;               (let ((n 0))
    n = 0;
    while ( l != NULL )    (while (not (null? l))
          ++n;               (set! n (1+ n))
          l = l->cdr;        (set! l (cdr l))
        }                   )
    return n;               n
  }                       ) )

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