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Operators and Assignments - Precedence
| Operator precdence (JPL pg 378) | |
| Operator type | Operators |
| Postfix | [] . (params) expr++ expr-- |
| Unary | ++expr --expr +expr -expr ~ ! |
| Creation or Cast | new (type)expr |
| Multiplicative | * / % |
| Additive | + - |
| Shift | << >> >>> |
| Relational | < > >= <= instanceof |
| Equality | == != |
| Bitwise AND | & |
| Bitwise exclusive OR | ^ |
| Bitwise inclusive OR | | |
| Logical AND | && |
| Logical OR | || |
| Ternary | ?: |
| Assignment | = += -= *= /= %= >>= <<= >>>= &= ^= |= |
- Precedence can be overridden using parantheses
5 + 3 * 2 // Result: 11
(5 + 3) * 2 // Result: 16
- when two operators of the same precedence are next to each other, associativity rules apply
- all binary operators (except assignment operators) are left-associative
- assignment is right-associative
a - b + c is evaluated as (a - b) + c
5 - 2 + 1 // Result: 4, not 2
a = b = c is evaluated as a = (b = c)
int a;
int b = 5;
int c = 1;
a = b = c; // Result: 1
Possible problem areas
- where boolean expressions are used to control loops
while( v = stream.next() != null )
processValue(v);
according to precedence rules, evaluates as
v = (stream.next() != null )
not the intended
(v = stream.next()) != null
