zoukankan      html  css  js  c++  java
  • c++优先级

    蒟蒻连c++的运算优先级都搞不清楚QAQ

    转载自http://www.cnblogs.com/chenglei/archive/2009/08/03/1537822.html



    C++优先级列表

     

    Precedence Operator Description Example Associativity
    1

    ()
    []
    ->
    .
    ::
    ++
    --

    Grouping operator
    Array access
    Member access from a pointer
    Member access from an object
    Scoping operator
    Post-increment
    Post-decrement

    (a + b) / 4;
    array[4] = 2;
    ptr->age = 34;
    obj.age = 34;
    Class::age = 2;
    for( i = 0; i < 10; i++ ) ...
    for( i = 10; i > 0; i-- ) ...







    left to right
    2

    !
    ~
    ++
    --
    -
    +
    *
    &
    (type)
    sizeof

    Logical negation
    Bitwise complement
    Pre-increment
    Pre-decrement
    Unary minus
    Unary plus
    Dereference
    Address of
    Cast to a given type
    Return size in bytes

    if( !done ) ...
    flags = ~flags;
    for( i = 0; i < 10; ++i ) ...
    for( i = 10; i > 0; --i ) ...
    int i = -1;
    int i = +1;
    data = *ptr;
    address = &obj;
    int i = (int) floatNum;
    int size = sizeof(floatNum);








    right to left
    3

    ->*
    .*

    Member pointer selector
    Member pointer selector

    ptr->*var = 24;
    obj.*var = 24;

    left to right
    4

    *
    /
    %

    Multiplication
    Division
    Modulus

    int i = 2 * 4;
    float f = 10 / 3;
    int rem = 4 % 3;

    left to right
    5

    +
    -

    Addition
    Subtraction

    int i = 2 + 3;
    int i = 5 - 1;

    left to right
    6

    <<
    >>

    Bitwise shift left
    Bitwise shift right

    int flags = 33 << 1;
    int flags = 33 >> 1;

    left to right
    7

    <
    <=
    >
    >=

    Comparison less-than
    Comparison less-than-or-equal-to
    Comparison greater-than
    Comparison geater-than-or-equal-to

    if( i < 42 ) ...
    if( i <= 42 ) ...
    if( i > 42 ) ...
    if( i >= 42 ) ...





    left to right
    8

    ==
    !=

    Comparison equal-to
    Comparison not-equal-to

    if( i == 42 ) ...
    if( i != 42 ) ...

    left to right
    9 & Bitwise AND flags = flags & 42; left to right
    10 ^ Bitwise exclusive OR flags = flags ^ 42; left to right
    11 | Bitwise inclusive (normal) OR flags = flags | 42; left to right
    12 && Logical AND if( conditionA && conditionB ) ... left to right
    13 || Logical OR int i = (a > b) ? a : b left to right
    14 ? : Ternary conditional (if-then-else) if( conditionA || conditionB ) ... right to left
    15

    =
    +=
    -=
    *=
    /=
    %=
    &=
    ^=
    |=
    <<=
    >>=

    Assignment operator
    Increment and assign
    Decrement and assign
    Multiply and assign
    Divide and assign
    Modulo and assign
    Bitwise AND and assign
    Bitwise exclusive OR and assign
    Bitwise inclusive (normal) OR and assign
    Bitwise shift left and assign
    Bitwise shift right and assign

    int a = b;
    a += 3;
    b -= 4;
    a *= 5;
    a /= 2;
    a %= 3;
    flags &= new_flags;
    flags ^= new_flags;
    flags |= new_flags;
    flags <<= 2;
    flags >>= 2












    right to left
    16 , Sequential evaluation operator for( i = 0, j = 0; i < 10; i++, j++ ) ... left to right

    ——by zhber,转载请注明来源
  • 相关阅读:
    基于域名的虚拟主机
    用户认证
    部署lnmp
    django开发流程
    sed 和awk的执行方式
    将文本行倒序排列
    《深入理解JAVA虚拟机》----------第二章 JAVA内存区域与内存溢出异常,笔记(上)
    《深入理解JAVA虚拟机》----------第三章 垃圾收集器与内存分配策略,笔记(下)
    《深入理解JAVA虚拟机》----------第三章 垃圾收集器与内存分配策略,笔记(上)
    洛谷P3783 [SDOI2017]天才黑客(前后缀优化建图+虚树+最短路)
  • 原文地址:https://www.cnblogs.com/zhber/p/4035914.html
Copyright © 2011-2022 走看看