binary to decimal

public class Javafunction{
    public static int binToDec(int n){
        int pow=0;
        int dec=0;
        while(n>0){
            int lastDigit=n%10;
            dec=dec+(lastDigit*(int)Math.pow(2, pow));
            pow++;
            n=n/10;
        }
        System.out.println(dec);
        return n;
    }   
    
    public static void main(String args[]){
        binToDec(100);
    } 
}