使用while循环读取文件在C ++中如何工作? [英] How does reading file with while loops work in C++?

问题描述

为什么可以使用while循环(如

Why is it possible to read a file using a while loop such as

while (file >> variable)

或

while (getline(xx, yy))

>>和getline函数是否返回布尔值?

Do the >> and getline functions return boolean values ?

推荐答案

流运算符求值是对流本身的引用.这允许链接例如file >> variable >> variable >> variable.

The stream operators evaluate to a reference to the stream itself. This allows chaining e.g. file >> variable >> variable >> variable.

将其与流对象可转换为布尔值(其值是true且未设置任何错误标志的情况)结合使用时，是的，您会得到这种效果.

When you combine it with the fact that the stream object is convertible to boolean (whose value is true iff no error flags are set) and, yes, you get that effect.

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