On Wed, 06 Sep 2017 01:04:17 +0300, Marko Rauhamaa wrote: > Chris Angelico <ros...@gmail.com>: > >> That shows that the Java '==' operator is like the Python 'is' >> operator, and checks for object identity. You haven't manipulated >> pointers at all. In contrast, here's a C program that actually >> MANIPULATES pointers: >> >> [...] >> >> You can't do this with Python, since pointer arithmetic fundamentally >> doesn't exist. You can in C. Can you in Java?
A necessary (but not sufficient) condition to be able to do pointer arithmetic is to actually have pointers as a data type. Pointers are not a data type in either Python or Java, so of course you can't do pointer arithmetic on them. If you don't have a pointer, you can't do arithmetic on it. Pointer arithmetic itself is not the issue. Java could have been like standard Pascal, and allow pointers as a first class data type (you can assign them to variables, pass them to functions, return them, have pointers to pointers, etc) without allowing pointer arithmetic. But they didn't -- Java the language doesn't include pointers as a value at all. > You can't do it in Pascal, either, but Pascal definitely has pointers. Not in standard Pascal, but most actual Pascal compilers let you perform pointer arithmetic. -- Steven D'Aprano “You are deluded if you think software engineers who can't write operating systems or applications without security holes, can write virtualization layers without security holes.” —Theo de Raadt -- https://mail.python.org/mailman/listinfo/python-list
