7.1 Assignment Operators
[This section corresponds to K&R Sec. 2.10]
The first and more general way is that any time you have the pattern
v = v op e
where v is any variable (or anything like a[i]), op is any of the binary arithmetic operators we've seen so far, and e is any expression, you can replace it with the simplified
v op= e
For example, you can replace the expressions
i = i + 1
j = j - 10
k = k * (n + 1)
a[i] = a[i] / b
with
i += 1
j -= 10
k *= n + 1
a[i] /= b
In an example in a previous chapter, we used the assignment
a[d1 + d2] = a[d1 + d2] + 1;
to count the rolls of a pair of dice. Using +=, we could simplify this expression to
a[d1 + d2] += 1;
As these examples show, you can use the ``op='' form with any of the arithmetic operators (and with several other operators that we haven't seen yet). The expression, e, does not have to be the constant 1; it can be any expression. You don't always need as many explicit parentheses when using the op= operators: the expression
k *= n + 1
is interpreted as
k = k * (n + 1)
