C+ +没有提供查询变量或表达式的类型的简便方法。

C + + has never had an easy mechanism for querying the type of a variable or an expression.

youdao

默认指定的子句可以为一个常量、一个特殊的寄存器、另一个全局变量、一个表达式或关键字 NULL。

The default clause specified can be either a constant, a special register, another global variable, an expression or the keyword NULL.

youdao

XPath表达式使用动态定类型(在对表达式或变量求值之前，不必知道表达式或变量的类型)。

XPath expressions use dynamic typing (the type of an expression or of a variable is not necessarily known until the expression or variable is evaluated).

youdao

So don't underestimate the value for the next week or two of just inserting printf statements into your code temporarily just to print out what the value of some variable is, or some expression is, so that you can just do a sanity check.

所以不要低估下一两周的重要性,虽然我们只将“printf“语句暂时地植入到,我们的代码中，只是用来打印一些,变量或表达式的值，所以你们提醒一下自己。

哈佛公开课 - 计算机科学课程节选