Question

Use your class to calculate rational approximations for π using the series π = 4 /1 − 4/ 3 + 4/ 5 − 4 /7 + . . . . Your program should ask the user how many terms to include in the approximation. For full credit, use the class above as much as possible (to do all the calculations).

Answer 1

import java.util.Scanner;

public class PiCalculation {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("How many terms do you want? ");
        int n = in.nextInt();
        double pi = 0;
        int sign = 1;
        for(int i = 0; i < n; ++i) {
            pi += (4 * sign) / (2*i + 1.0);
            sign = -sign;
        }
        System.out.println("Calculated value of pi is " + pi);
    }

}