Question 18

class AproxPI{
    public static void main (String[] args){
        AproxPI p = new AproxPI();
        System.out.println(p.aprox_pi(5));
    }

    public double aprox_pi(int term){
        double pi = 1.0;
        double denominator = 3.0;
        boolean is_addition = false;
        int i;
        for(i=0; i<=term; i++){
            if(is_addition){
                pi = pi + (1.0/denominator);
                is_addition = false;
            }
            else{
                pi = pi - (1.0/denominator);
                is_addition = true;
            }
            denominator = denominator + 2.0;
        }
        return (4*pi);
    }
}