Sample data sets with std::sample

The std::sample() algorithm takes a random sample of a sequence of values and populates a destination container with the sample. It is useful for analyzing a larger set of data, where the random sample is taken to be representative of the whole.

A sample set allows us to approximate the characteristics of a large set of data, without analyzing the full set. This provides efficiency in exchange for accuracy, a fair trade-off in many circumstances.

How to do it…

In this recipe, we'll use an array of 200,000 random integers, with standard normal distribution. We'll sample a few hundred values to create a histogram of the frequency of each value.

• We'll start with a simple function to return a rounded int from a double. The standard library lacks such a function and we'll need it later:

  int iround(const double& d) {
      return static_cast<int>(std::round(d));
  }

The standard...