using_rand.cpp

// an example of reading random numbers from /dev/urandom
// https://stackoverflow.com/questions/35726331/c-extracting-random-numbers-from-dev-urandom
#include <iostream>
#include <fstream>
int main(void) {

    // open /dev/urandom to read
    std::ifstream urandom("/dev/urandom");

    // check that it did not fail
    if (urandom.fail()) {
        std::cerr << "Error: cannot open /dev/urandom\n";
        return 1;
    }

    // read a random 8-bit value.
    // Have to use read() method for low-level reading
    char ch = 'a';
    urandom.read(&ch, 1);
    // cast to integer to see the numeric value of the character
    std::cout << "Random character: " << (unsigned int)ch << "\n";

    // read another 8-bit value
    urandom.read(&ch, 1);
    std::cout << "Random character: " << (unsigned int)ch << "\n";

    // read a random unsigned int
    unsigned int num = 42;
    urandom.read((char*)&num, sizeof(int));
    std::cout << "Random character: " << num << "\n";

    // close random stream
    urandom.close();
    return 0;
}