Java Monthly Compound Interest Program

import java.util.Scanner;

class calculator{

private double interest_principal, month_interest, interest_amount;
private double principal  = 1000;
private int a, c;

        double cinterest (int x){
        interest_amount = Math.pow(1 + 2.65/100, x) - 1;
        return(interest_amount * principal);
        }
}

class intcalc{

        public static void main(String[] args){

                calculator interest = new calculator();
                Scanner uinput = new Scanner(System.in);
                int months[] = {2, 5, 10, 500};
                int user_months;

                        for(int b=0;b<4;b++){
                                System.out.println("Interest at " +
                                months[b] + " months is: " + interest.cinterest(months[b]));

                        }
                System.out.print("Enter # of months for interest calculation: ");
                user_months = uinput.nextInt();
                System.out.println("Interest amount after " + user_months + " months is: "
                                                + interest.cinterest(user_months));
        }

}