Program to Find the Terms of an Expansion

/**
 * Just a random program for 'Binomial Theorem' (Class-XI Maths).
 */
import java.util.*;
public class Binomial_Theorem
{
    static long fact(int num) //Function to find factorial of a number.
    {
        int i;
        long f=1;
        for(i=1;i<=num;i++)
        {
            f *= i;
        }

        return f;
    }

    static long combination(int n, int r) //Function to find the combination required for a term.
    {
        long comb = fact(n) / (fact(n-r)*fact(r));
        return comb;
    }

    static void findExpansion(char a, char b, int power) //Function to find the terms of an expansion.
    {
        int i;
        String aterm = "";
        String bterm = "";
        String term;
        long ncr; String ncrterm = "";
        for(i=0;i<=power;i++)
        {
            ncr = combination(power, i);
            ncrterm = Long.toString(ncr); //nCr.
            aterm = Character.toString(a) + "^" + Integer.toString(power - i); //a^n-r
            bterm = Character.toString(b) + "^" + Integer.toString(i); //b^r
            term = ncrterm + " * " + aterm + " * " + bterm;
            System.out.println("Term "+(i+1)+" = "+term);
        }
    }

    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);

        System.out.println("Please enter the first variable in (a+b)^n.");
        char a = sc.next().charAt(0);

        System.out.println("Please enter the second variable in (a+b)^n.");
        char b = sc.next().charAt(0);

        System.out.println("Please enter 'n' in (a+b)^n.");
        int power = sc.nextInt();

        findExpansion(a, b, power);

        sc.close();
    }
}