Java's Assignment Operators
The most basic assignment operator is '='.
However, in Java, any arithmetic or bitwise operator can be joined to '=' to form a composite assignment operator. For example:
a[func()] += 1; is equivalent to a[func()] = a[func()] + 1;
However, in the first case, func() is called only once. Since it may return a new value when called a second time, we cannot be sure whether or not it is the same array element that is being referred on both the left and right hand sides of the '=' sign. The composite '+=' operator is therefore clearer and more predictable in operation when a function is used as an array indexer.
If var is a variable of type Type, then
var op= expr is equivalent to var = (Type)((var) op (expr))
Note that the whole of expr is bound tightly. For example:
a *= b + 1; is equivalent to a = a * (b + 1);
not a = a * b + 1;
Although a += 1; is the same as ++a; the ++ is traditionally the preferred coding.
© 1998 Robert John Morton