Iteration over wave file data: revisited

3 lutego 2013 11:42 tags:

The iteration example has been updated using some features from C++11:

Compare with previous version of this example.

#include "aquila/global.h"
#include "aquila/source/WaveFile.h"
#include <algorithm>
#include <cstdlib>
#include <iostream>

int main(int argc, char *argv[])
{
    if (argc < 2)
    {
        std::cout << "Usage: wave_iteration <FILENAME>" << std::endl;
        return 1;
    }

    Aquila::WaveFile wav(argv[1]);
    std::cout << "Loaded file: " << wav.getFilename()
              << " (" << wav.getBitsPerSample() << "b)" << std::endl;
    Aquila::SampleType maxValue = 0, minValue = 0, average = 0;

    // simple index-based iteration
    for (std::size_t i = 0; i < wav.getSamplesCount(); ++i)
    {
        if (wav.sample(i) > maxValue)
            maxValue = wav.sample(i);
    }
    std::cout << "Maximum sample value: " << maxValue << std::endl;

    // iterator usage
    for (auto it = wav.begin(); it != wav.end(); ++it)
    {
        if (*it < minValue)
            minValue = *it;
    }
    std::cout << "Minimum sample value: " << minValue << std::endl;

    // range-based for loop
    for (auto sample : wav)
    {
        average += sample;
    }
    average /= wav.getSamplesCount();
    std::cout << "Average: " << average << std::endl;

    // STL algorithms work too, so the previous examples could be rewritten
    // using max/min_element.
    int limit = 5000;
    int aboveLimit = std::count_if(
        wav.begin(),
        wav.end(),
        [limit] (Aquila::SampleType sample) {
            return sample > limit;
        }
    );
    std::cout << "There are " << aboveLimit << " samples greater than "
              << limit << std::endl;

    return 0;
}
« Return to list