Ken Wellsch: I'm fairly sure things like "=+" and so on were replaced with "+=" in the move from V6 to V7. I think structure assignments were added here too, and the much more obscure, being able to declare passed arguments in the function preamble as "register." I believe K&R reflects the C language as seen with V7... The V7 C compiler accepted =+, but it still accepted += as well; there was a lot of code written the old way, and nobody wanted to be forced to convert everything all at once. Similarly, the V7 compiler complained about implicit conversions between pointers of different types, or between ints and pointers, but they were treated as warnings, not fatal errors; you could still compile old code and just ignore the compiler's fussing. I recall that when I arrived at Bell Labs in 1984, it was apparently not long after the research group's C compiler had been changed to treat all the obsolete stuff as errors; certainly there was still code in /usr/src that hadn't been updated, and all of it had been recompiled recently to run on the VAX. A modern C compiler would choke even on some of the stuff that was legal in those days. Recently I recompiled tbl with lcc, and had a grand time cleaning out all the ideas we all thought were clever in the late 1970s but most of us would never think of doing now. For those with the virgin source handy, take a look at subroutine `point' and the way it is used and abused. Norman Wilson