[英]Confusion with syntax for postfix expressions and operators
In the following case, 在以下情况下,
int i = 0;
int j = 42;
i = j++;
I know ++
is posfix operator, So, is j
a posfix expression or should you say j++
is posfix expression ? 我知道
++
是posfix运算符,所以, j
是posfix表达式还是应该说j++
是posfix表达式?
Syntactically, both j
and j++
are postfix-expressions. 从语法上讲,
j
和j++
都是后缀表达式。
See the grammar in section 5.2 of the C++ 2003 standard: 请参阅C ++ 2003标准的5.2节中的语法:
postfix-expression:
primary-expression
...
postfix-expression ++
( j
is also a primary-expression; j++
is not.) (
j
也是主要表达式; j++
不是。)
The fact that a primary-expression is a kind of postfix-expression (even if it doesn't contain a postfix operator) is mostly a matter of convenience for defining the language syntax. 主表达式是一种后缀表达式(即使它不包含后缀运算符),这一事实主要是为了方便定义语言语法。 There's not much point in referring to
j
as a postfix-expression unless you're talking about parsing C++ (or C) source code. 除非您正在谈论解析C ++(或C)源代码,否则将
j
称为后缀表达式没有多大意义。
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