#include <iostream>
#include <string>

using namespace std;

int main()
{  
   const double FLUID_OUNCE_TO_LITER = 0.029586;   
   const double GALLON_TO_LITER = 3.758;
   const double OUNCE_TO_GRAM = 28.3495;
   const double POUND_TO_GRAM = 453.6;
   const double INCH_TO_METER = 0.00254;
   const double FOOT_TO_METER = 0.305;   
   const double MILE_TO_METER = 1609.0;
   
   cout <<  "Convert from? (fl.oz, gal, oz, lb in, ft, mi) ";
   string from;
   cin >> from;

   cout <<  "Convert to? (ml, l, kg, mm, cm, m, km) ";      
   string to;
   cin >> to;

   cout <<  "Value ? : ";
   double value;
   cin >> value;

   double cfactor = 0.0;
          
   if (from == "fl.oz")
   {  
      if (to == "ml")
         cfactor = FLUID_OUNCE_TO_LITER * 1000;
      else if (to == "l")
         cfactor = FLUID_OUNCE_TO_LITER;             
   }
   else if (from == "gal")
   {  
      if (to == "ml")
         cfactor = GALLON_TO_LITER * 1000;
      else if (to == "l")
         cfactor = GALLON_TO_LITER;
   }
   else if (from == "oz")
   {  
      if (to == "g")
         cfactor = OUNCE_TO_GRAM;
      else if (to == "kg")
         cfactor = OUNCE_TO_GRAM / 1000;
   }
   else if (from == "lb")
   {  
      if (to == "g")
         cfactor = POUND_TO_GRAM;
      else if (to == "kg")
         cfactor = POUND_TO_GRAM / 1000;
   }
   else if (from == "in")
   {  
      if (to == "mm")
         cfactor = INCH_TO_METER * 1000;
      if (to == "cm")
         cfactor = INCH_TO_METER * 100;
      else if (to == "m")
         cfactor = INCH_TO_METER;
      else if (to == "km")
         cfactor = INCH_TO_METER / 1000;
   }
   else if (from == "ft")
   {  
      if (to == "mm")
         cfactor = FOOT_TO_METER * 1000;
      if (to == "cm")
         cfactor = FOOT_TO_METER * 100;
      else if (to == "m")
         cfactor = FOOT_TO_METER;
      else if (to == "km")
         cfactor = FOOT_TO_METER / 1000;
   }
   else if (from == "mi")
   {  
      if (to == "mm")
         cfactor = MILE_TO_METER * 1000;
      if (to == "cm")
         cfactor = MILE_TO_METER * 100;
      else if (to == "m")
         cfactor = MILE_TO_METER;
      else if (to == "km")
         cfactor = MILE_TO_METER / 1000;
   }
   
   if (cfactor == 0.0)
      cout << "Requested conversion " << from << " -> " 
         << to << " is not available.\n";
   else
   {  
      double converted = value * cfactor;
      cout <<  value << " " << from  
         << " = " << converted << " " << to << "\n";
   }
      
   return 0;                                 
}