c语言的操作符共有15个优先级，如下：
Operators Associativity
() [] -> . left to right
! ~ ++ -- + - * (type) sizeof right to left
* / % left to right
+ - left to right
<< >> left to right
< <= > >= left to right
== != left to right
& left to right
^ left to right
| left to right
&& left to right
|| left to right
?: right to left
= += -= *= /= %= &= ^= |= <<= >>= right to left
, left to right
优先级从上到下依次递减，最上面具有最高的优先级，逗号操作符具有最低的优先级。
所有的优先级中，只有三个优先级是从右至左结合的，它们是单目运算符、条件运算符、赋值运算符。其它的都是从左至右结合。
具有最高优先级的其实并不算是真正的运算符，它们算是一类特殊的操作。()是与函数相关，[]与数组相关，而－>及.是取结构成员。
其次是单目运算符，所有的单目运算符具有相同的优先级，因此在我认为的 真正的运算符中它们具有最高的优先级，又由于它们都是从右至左结合的，因此*p++与*(p++)等效是毫无疑问的。
接下来是算术运算符，*、/、%的优先级当然比+、－高了。
移位运算符紧随其后。
其次的关系运算符中，< <= > >=要比 == !=高一个级别，不大好理解。
所有的逻辑操作符都具有不同的优先级（单目运算符出外，！和~）
逻辑位操作符的"与"比"或"高，而"异或"则在它们之间。
跟在其后的&&比||高。
接下来的是条件运算符，赋值运算符及逗号运算符。
在C语言中，只有4个运算符规定了运算方向，它们是&&、| |、条件运算符及赋值运算符。
&&、| |都是先计算左边表达式的值，当左边表达式的值能确定整个表达式的值时，就不再计算右边表达式的值。如 a = 0 && b; &&运算符的左边位0，则右边表达式b就不再判断。
在条件运算符中。如a?b:c；先判断a的值，再根据a的值对b或c之中的一个进行求值。
赋值表达式则规定先对右边的表达式求值，因此使 a = b = c = 6;成为可能。
C++运算符优先级
Operator Description Example Overloadable Group 1 (no associativity) ::Scope resolution operatorClass::age = 2;NOGroup 2 ()Function callisdigit('1')YES()Member initalization c_tor(int x, int y) : _x(x), _y(y*10){};YES[]Array accessarray = 2;YES->Member access from a pointerptr->age = 34;YES.Member access from an objectobj.age = 34;NO++Post-incrementfor( int i = 0; i < 10; i++ ) cout << i;YES--Post-decrementfor( int i = 10; i > 0; i-- ) cout << i;YESconst_castSpecial castconst_cast<type_to>(type_from);NOdynamic_castSpecial castdynamic_cast<type_to>(type_from);NOstatic_castSpecial caststatic_cast<type_to>(type_from);NOreinterpret_castSpecial castreinterpret_cast<type_to>(type_from);NOtypeidRuntime type informationcout « typeid(var).name();
cout « typeid(type).name();NOGroup 3 (right-to-left associativity) !Logical negationif( !done ) …YESnotAlternate spelling for ! ~Bitwise complementflags = ~flags;YEScomplAlternate spelling for ~ ++Pre-incrementfor( i = 0; i < 10; ++i ) cout << i;YES--Pre-decrementfor( i = 10; i > 0; --i ) cout << i;YES-Unary minusint i = -1;YES+Unary plusint i = +1;YES*Dereferenceint data = *intPtr;YES&Address ofint *intPtr = &data;YESnewDynamic memory allocationlong *pVar = new long;
MyClass *ptr = new MyClass(args);YESnew []Dynamic memory allocation of arraylong *array = new long[n];YESdeleteDeallocating the memorydelete pVar;YESdelete []Deallocating the memory of arraydelete [] array;YES(type)Cast to a given typeint i = (int) floatNum;YESsizeofReturn size of an object or typeint size = sizeof floatNum;
int size = sizeof(float);NOGroup 4 ->*Member pointer selectorptr->*var = 24;YES.*Member object selectorobj.*var = 24;NOGroup 5 *Multiplicationint i = 2 * 4;YES/Divisionfloat f = 10.0 / 3.0;YES%Modulusint rem = 4 % 3;YESGroup 6 +Additionint i = 2 + 3;YES-Subtractionint i = 5 - 1;YESGroup 7 <<Bitwise shift leftint flags = 33 << 1;YES>>Bitwise shift rightint flags = 33 >> 1;YESGroup 8 <Comparison less-thanif( i < 42 ) …YES<=Comparison less-than-or-equal-toif( i <= 42 ) ...YES>Comparison greater-thanif( i > 42 ) …YES>=Comparison greater-than-or-equal-toif( i >= 42 ) ...YESGroup 9 ==Comparison equal-toif( i == 42 ) ...YESeqAlternate spelling for == !=Comparison not-equal-toif( i != 42 ) …YESnot_eqAlternate spelling for != Group 10 &Bitwise ANDflags = flags & 42;YESbitandAlternate spelling for & Group 11 ^Bitwise exclusive OR (XOR)flags = flags ^ 42;YESxorAlternate spelling for ^ Group 12 |Bitwise inclusive (normal) ORflags = flags | 42;YESbitorAlternate spelling for | Group 13 &&Logical ANDif( conditionA && conditionB ) …YESandAlternate spelling for && Group 14 ||Logical ORif( conditionA || conditionB ) ...YESorAlternate spelling for || Group 15 (right-to-left associativity) ? :Ternary conditional (if-then-else)int i = (a > b) ? a : b;NOGroup 16 (right-to-left associativity) =Assignment operatorint a = b;YES+=Increment and assigna += 3;YES-=Decrement and assignb -= 4;YES*=Multiply and assigna *= 5;YES/=Divide and assigna /= 2;YES%=Modulo and assigna %= 3;YES&=Bitwise AND and assignflags &= new_flags;YESand_eqAlternate spelling for &= ^=Bitwise exclusive or (XOR) and assignflags ^= new_flags;YESxor_eqAlternate spelling for ^= |=Bitwise normal OR and assignflags |= new_flags;YESor_eqAlternate spelling for |= <<=Bitwise shift left and assignflags <<= 2;YES>>=Bitwise shift right and assignflags >>= 2;YESGroup 17 throwthrow exceptionthrow EClass(“Message”);NOGroup 18 ,Sequential evaluation operatorfor( i = 0, j = 0; i < 10; i++, j++ ) …YES |