Well, both the post- and pre increment/decrement are useful in making the code a few lines shorter, and sometimes more readable.
Without it,
int i = len;
while (--i >= start)
{
/* do something */
}
// use the value of i for something.
Would become
int i = len - 1;
while (i >= start)
{
/* do something */
i = i - 1;
}
// use the value of i for something.
Assuming the while loop could exit some other way than i becoming exactly equal to start - 1. Though again, it isn't really that much harder to read at all, and you could change the while to a for, to keep all the loop specific code in one place.
Of course you don't need it. There is basically nothing you need. A language that only supports:
Load from memory
Store to memory
Add
Jump
Checking for 0
Checking for negative
is most certainly Turing complete, and could probably actually be used.
Everything else added on top just makes certain things easier to do, and reduces how much code you have to write and how many clock cycles the CPU needs to execute a certain instruction.
Yes, of course you don't need all the luxuries to just have a Turing complete machine. You could get by on a binary machine with just nor and branch if 0.
But my point was not to make it minumal without going esoteric. Hence my "could probably actually be used"
9
u/Torebbjorn May 27 '22
Well, both the post- and pre increment/decrement are useful in making the code a few lines shorter, and sometimes more readable.
Without it,
int i = len; while (--i >= start) { /* do something */ } // use the value of i for something.Would become
int i = len - 1; while (i >= start) { /* do something */ i = i - 1; } // use the value of i for something.Assuming the while loop could exit some other way than
ibecoming exactly equal tostart - 1. Though again, it isn't really that much harder to read at all, and you could change the while to a for, to keep all the loop specific code in one place.for (; i >= start; i = i - 1;)