CSIT 212 Data Structures Assignment Dr. H. Johnson

Example 1a: FactorialCalculation.java

//The Recursive Factorial Method

public class FactorialCalculation { //recursive Factorial method

public long factorial(long number) { if (number <= 1) return 1; else return number * factorial (number 1); } //Now output the factorials of 0 through 15 public void displayFactorials() { // Calculate the factorial of o through 10

for ( int counter = 0; counter <= 10; counter++ ) System.out.print ( %d! = %d , counter, factorial (counter )); } // end of the method displayFactorials } // end of class FactorialCalculation

Example 1b: FactorialTest.java // Testing the recursive factorial method

public class FactorialTest { // calculate the factorial of 0 10

Public static void main ( String args[] ) { factorialCalculation factorialCalculation = new FactorialCalculation(); factorialCalculation.displayFactorials(); } // end of main

} // end of the class FactorialTest

Recursive and Iterative Activities:

1. Use a java editor to write and execute the example given above. Copy your source code as well as the output as an image to a word processor.

2. Write another method that uses loop, instead of recursion, to calculate the factorial of the previous example.

3. Use the time method (Java.System.currentTimeMillis()) to compare execution times for the two methods ((i) the recursive version and (ii) the loop version) when calculating 15! 30! 50! 90!

4. Draw a graph that shows the difference in time for the method for values in part 3.

Note:

In the code given above, if you encounter issues with the type long integer, try big integer instead.