Question

Write code to complete doublePennies()'s base case. Sample output for below program with inputs 1 and 10: Number of pennies after 10 days: 1024 Note: If the submitted code has an infinite loop, the system will stop running the code after a few seconds, and report "Program end never reached." The system doesn't print the test case that caused the reported message.

Answer 1

Answer:

public class CalculatePennies {

// Returns number of pennies if pennies are doubled numDays times

  public static long doublePennies(long numPennies, int numDays) {

     long totalPennies = 0;

     /* Your solution goes here */

     if(numDays == 0){

         totalPennies = 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

  public static void main (String [] args) {

     long startingPennies = 0;

     int userDays = 0;

     startingPennies = 1;

     userDays = 10;

     System.out.println("Number of pennies after " + userDays + " days: "

          + doublePennies(startingPennies, userDays));

     return;

  }

}

Explanation: