Approximating pi with the Leibniz formula

leibniz.java

class Leibniz {
	public static void main(String[] args) {
		Leibniz test = new Leibniz();
		System.out.println(test.leibnizPi(0));
		System.out.println(test.leibnizPi(-1));
		System.out.println(test.leibnizPi(-4));
	}
	
	public double leibnizPi(int accuracy) {
		double target_accuracy = Math.pow(10, accuracy);
		
		double acc = 1.0;
		int sub = 3;
		int sign = -1;
		
		while ( Math.abs(4.0 * acc - Math.PI) > target_accuracy ) {
			acc += sign * ( 1.0 / sub );
			sign *= -1;
			sub += 2;
		}
		
		return 4.0 * acc;
	}
}