If you are planning to use a predefined class or structure in your code, you must determine whether it has a default property, and if so, what its name is.

如果您计划在代码中使用预定义类或结构，则必须确定它是否具有默认属性；如果有，还必须确定其名称。

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If you are planning to use a predefined class or structure in your code, you must determine whether it has a default property, and if so, what its name is.

如果您计划在代码中使用预定义类或结构，则必须确定它是否具有默认属性；如果有，还必须确定其名称。

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