avoid rounding error (floating specifically) c++

Question

http://www.learncpp.com/cpp-tutorial/25-floating-point-numbers/ I have been about this lately to review C++.

In general computing class professors tend not to cover thes

Answer 1

In other words, to minimize rounding errors, it can be helpful to keep numbers in decimal fixed-point (and actually work with integers).

#include 
#include 

int main() {

  using namespace std;

  cout << setprecision(17);

  double v1=1, v1D=10; 
  cout << v1/v1D << endl;  // 0.10000000000000001


  double v2=3, v2D=1000;  //0.0030000000000000001
  cout << v2/v2D << endl;

  // v1/v1D + v2/v2D = (v1*v2D+v2*v1D)/(v1D*v2D)

  cout << (v1*v2D+v2*v1D)/(v1D*v2D) << endl; // 0.10299999999999999

}