There are five iterator categories: input, output, forward, bidirectional, and random access.

标准库定义了五种迭代器类别：输入、输出、前向、双向和随机访问迭代器。

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According to the signal can be divided into sine wave signal, function (wave) signals, pulse signals and random signal generator, and other four major categories.

按信号波形可分为正弦信号、函数(波形)信号、脉冲信号和随机信号发生器等四大类。

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In the ad serving phase, when your computer requests an advert from the OIX (because a website has included our tag in their page), the browser sends the random number and the categories are used to deliver the targeted ad, not the details of your browsing, or anything about you or your computer.

BBC: Phorm: Your questions answered

And while the collection of products and categories may seem random windows, furniture, floor coverings, books the common thread is that all are targeted to the busy moms populating most of America.

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There is, in essence, no data other than the categories and the random number stored in the system and so it's impossible to know (or indeed reverse engineer from that) who you are or where you've been.

BBC: Phorm: Your questions answered