text: #include <iostream>
  using namespace std;
  
  // Returns number of pennies if pennies are doubled numDays times
  long long DoublePennies(long long numPennies, int numDays){
     long long totalPennies = 0;
  
     /* Your solution goes here  */
     if(numDays == 0)
        return numPennies;
  
     else {
        totalPennies = DoublePennies((numPennies * 2), numDays - 1);
     }
  
     return totalPennies;
  }
  
  // Program computes pennies if you have 1 penny today,
  // 2 pennies after one day, 4 after two days, and so on
  int main() {
     long long startingPennies = 0;
     int userDays = 0;
  
     startingPennies = 1;
     userDays = 10;
     cout << "Number of pennies after " << userDays << " days: "
          << DoublePennies(startingPennies, userDays) << endl;
     return 0;
  }
  