Resources
Operator Precedence
|
| Operators |
Associativity |
|
:: |
left to right HIGH |
|
() [] -> . |
left to right |
++(postfix) --(postfix) typeid
static_cast dynamic_cast const_cast
reinterpret_cast |
right to left |
|
++(prefix) --(prefix) |
left to right |
! +(unary) -(unary) * &
new delete delete []
(type) sizeof |
right to left |
|
.* ->* |
left to right |
|
* / % |
left to right MEDIUM |
|
+(binary) -(binary) |
left to right |
|
<< >> |
left to right |
|
< <= > >= |
left to right |
|
== != |
left to right |
|
&& |
left to right |
|
|| |
left to right |
|
= += -= *= /= %= &= ^= |= <<=
>>= |
right to left |
|
?: |
right to left LOW |
|
, |
left to right |
|
|
|
Unary +, - and * have higher precedence than the binary
forms. The operator () refers to function or constructor
call.
Precedence determines the order in which
operands are bound to operators. Operators on the same line
have the same precedence; rows are in order of decreasing
precedence. C++ does not specify the order in
which the operands of an operator are evaluated. Similarly,
the order in which function arguments are evaluated is not
specified. Examples:
x = f() + g(); a[i] = i++;
printf("%d %d\n",++n,power(2,n)); z = x / ++x;
|
Programs should not depend upon the order of
evaluation of expressions, except as guaranteed by ANSI C++
for the following operators:
1. a, b comma operator (not the comma between arguments)
2. a && b logical and
3. a || b logical or
4. a ? b : c conditional
|
All of these guarantee that expression a will be
computed before expression b (or c).
In addition, when a function-call takes place all
arguments are evaluated before control transfers to the
function.
ANSI C++ guarantees that each full expression will be
evaluted before going on.
|
|
|