#include <iostream>
#include <fstream>

using namespace std;

int main() {
  double weight;
 
  while (true) {
    cout << "Enter your weight: ";
    cin >> weight;
 
    if (cin.fail()) {
      // We failed to extract a double
      cin.clear();           // reset stream state to goodbit.
      cin.ignore(256, '\n'); // remove any input from the stream until \n
      continue;
    }
 
    if (weight <= 0)
      continue;
 
    break;
  }
 
  cout << "You weight is: " << weight << endl;
}