#include <iostream>
#include <cstdlib>
#include <string>
using namespace std;

struct planetacc {
	string body;
	double gravity;
};

void convert(double& weightlb, double& weightkg, double gravity) {
	weightkg = (weightlb * 0.45359237) / 9.8 * gravity;
}

int main (){
	cout << "Type in a planet to know the weight of something over there.\n";
	string pick;
	cin >> pick;

        static const planetacc aduetog[]{
                {"earth", 9.81},
                {"mercury", 3.7},
                {"venus", 8.87},
                {"mars", 3.71},
                {"jupiter",24.79},
                {"saturn", 10.44},
                {"uranus", 8.69},
                {"neptune", 11.15}
        };

        static const int a {size(aduetog)};

        int planetpick = -1;
        for (int i {0}; i < a; i++) {
                if (pick == aduetog[i].body) {
                        planetpick = i;
                        break;
                }
        }
        if (planetpick == -1) {
                cerr << "We couldn't find that planet here.\n";
                return EXIT_FAILURE;
        }

	cout << "Type in the weight in pounds.\n";
	double weightlb{0};
	cin >> weightlb;

	if (weightlb < 0) {
		cerr << "Lets not go lower than 0.\n";
		return EXIT_FAILURE;
	}


	double weightkg {0};

	convert(weightlb, weightkg,  aduetog[planetpick].gravity);

	cout << "This weighs " << weightkg << " kg on " << pick << "\n";
	return EXIT_SUCCESS;
}