Magical c++ snippets

magicalCPP.cpp

//discards all input in the standard input stream up to and including the first newline.
#include <limits>
cin.ignore(numeric_limits<streamsize>::max(), '\n'); 

//This is a string of special characters that clears the terminal on both linux and windows.
cout << "\033[2J\033[1;1H";

//This rolls a random number, but I'm not happy with it
//because it seems to segfault if it's passed a negative number
//for now, force anything less than 1 to become 1.
int rng(int number) {
  if (number < 1) {
      cout << endl << number << " is less than 1!!! (minor bug)\n";
      number = 1;
  }
    random_device dev;
    mt19937 rng(dev());
    uniform_int_distribution<int> dist{1, number};
  
// return true if the difference between a and b is extremely close,
// or within 0.1% percent of the larger of a and b
bool approximatelyEqualAbsRel(double a, double b, double absEpsilon = 1e-12, double relEpsilon = 0.001)
{
    // Check if the numbers are really close -- needed when comparing numbers near zero.
    double diff{ std::abs(a - b) };
    if (diff <= absEpsilon)
        return true;
 
    // Otherwise fall back to Knuth's algorithm
    return (diff <= (std::max(std::abs(a), std::abs(b)) * relEpsilon));
}
    return dist(rng);
}