Expressions and statements
Expressions are formed from operators and operands, the operand itself also be an expression.
Semicolon after expression constitutes statement.
In C ++ operator precedence
- Operator determines the order of priority values for the operator.
- C ++ operator is divided into 18 groups. The smaller the group the higher the priority.
- If two operators are used in the same operand, the first application of the highest priority operator.
- If two operators have the same priority level, the use of C ++ binding rules to determine which operator to binding.
- Binding of the same priority and the same set of operators.
- Associativity from left to right than the left represents the first application of most operators, and right-to-left combination represents the first application of the rightmost operator.
- Calculation, () has the highest priority, arithmetic> Relations> Logic> Conditions> assignment> comma (not absolute).
- Unary> binary operator> ternary operator (not absolute).
- Clear and specific binding of priority, you can add ().
| Operators | Associativity | meaning |
| The first priority group | ||
| :: | Scope resolution operator | |
| The second set of priorities | ||
| (expression) | Packet | |
| () | L-R | Function call |
| () | Configuration values, i.e. type (expr) | |
| [] | Array subscript | |
| -> | Indirect member operator | |
| . | Direct member operator | |
| const_cast | Special type conversion | |
| dynamic_cast | Special type conversion | |
| reinterpret_cast | Special type conversion | |
| static_cast | Special type conversion | |
| typeid | Type Id | |
| ++ | 1 plus operator, Suffix |
|
| -- | Save Operators 1, Suffix | |
| The third priority group (all unary) | ||
| ！ | R-L | Logical NOT |
| ~ | Non-bit | |
| + | Unary plus, a positive sign |
|
| - | Unary minus, minus | |
| ++ | 1 plus operator, the prefix | |
| -- | Save 1 operator, the prefix | |
| & | address | |
| * | Dereferencing (indirect value) | |
| () | Type conversion, that (type) expr | |
| sizeof | The length, in bytes | |
| new | Dynamic memory allocation | |
| new [] | Dynamically allocated arrays | |
| delete | Dynamic memory release | |
| delete | Dynamic Array release |
|
| The fourth priority group | ||
| .* | L-R | Members dereference |
| ->* | Indirect members dereference | |
| A fifth priority group (all binary operator) | ||
| * | L-R | Multiply |
| / | except | |
| % | Modulus (remainder) | |
| Priority sixth group (all binary operator) | ||
| + | L-R | plus |
| - | Less | |
| Priority seventh group | ||
| << | L-R | The left |
| >> | Right | |
| Priority eighth group | ||
| < | L-R | Less than |
| <= | less than or equal to | |
| >= | greater than or equal to | |
| > | more than the | |
| Priority ninth group | ||
| == | L-R | equal |
| != | not equal to | |
| Priority Group 10 (unary) | ||
| & | L-R | Bitwise AND |
| 优先级第十一组 | ||
| ^ | L-R | 按位 XOF(异或) |
| 优先级第十二组 | ||
| | | L-R | 按位 OR |
| 优先级第十三组 | ||
| && | L-R | 逻辑 AND |
| 优先级第十四组 | ||
| || | L-R | 逻辑 OR |
| 优先级第十五组 | ||
| ?: | R-L | 条件 |
| 优先级第十六组 | ||
| = | R-L | 简单赋值 |
| *= | 乘并赋值 | |
| /= | 除并赋值 | |
| %= | 求模并赋值 | |
| += | 加并赋值 | |
| -= | 减并赋值 | |
| &= | 按位 AND 并赋值 | |
| ^= | 按位 XOR 并赋值 | |
| |= | 按位 OR 并赋值 | |
| <<= | 左移并赋值 | |
| >>= | 右移并赋值 |
|
| 优先级第十七组 | ||
| throw | L-R | 引发异常 |
| 优先级第十八组 | ||
| , | L-R | 将两个表达式合并为一个 |
