- i++ is equivalent to i=i+1.
This (and the i- decrementing operator) is a common
contraction. The operation can be done after the variable is used,
or (by using -i, ++i) before, so
...
i = 4;
printf("i = %d\n", i++)
and
...
i = 4;
printf("i = %d\n", ++i)
will both leave i as 5, but in the 1st fragment 4 will be
printed out while in the 2nd 5 will.
- i+=6 is equivalent to i=i+6. This style of contraction isn't so common,
but can be used with most of the binary operators.
- Assignment statements have a value - the final value of the left-hand-side - so
j = (i=3+4) will set i then j to 7, and
i = j = k = 0 will set k, then j, then i to zero.
This feature should be used with caution.
- The `,' operator is used between 2 expressions if the
value of the 1st expression can be ignored. It's a way to put 2 or
more statements
where normally only one would go. E.g.
for(init(3),i=0,j+0; i<100; i++,j++)
This feature is often over-used too.
- Expressions with comparison operators return 1 if the comparison
is true, 0 if false, so while(i!=0) and while(i) are
equivalent.
- The `if (cond) exp1; else exp2;' construction can be abbreviated
using `(cond)?exp1:exp2'. The following fragments are equivalent.
...
if (a==6)
j=7;
else
j=5;
...
(a==6)?j=7:j=5;
...
This notation should be used with discretion.
