package sedion.jeffli.action;
import java.util.ArrayList;import java.util.Stack;

/**
 * My Open-Source road
 * @author Jeff Li
 *
 * @param <T>
 */
public class ALStack<T> extends Stack<T> {
    
    /**
     * 
     */
    private static final long serialVersionUID = -1261738006146239371L;
    private ArrayList<T> stackList = null;
    
    //create an empty stack by creating an empty ArrayList
    public ALStack(){
        stackList = new ArrayList<T>();
    }
    
}

package sedion.jeffli.action;

import java.util.Scanner;


public class BaseStr {
    public static void main(String[] args) {
        int num , b;
        Scanner keyIn = new Scanner(System.in);
        
        System.out.print("Enter a decimal number: ");
        num = keyIn.nextInt();
        
        System.out.print("Enter a base (2 to 16): ");
        b = keyIn.nextInt();
        System.out.print(" "+num+" base "+b+" is "+baseString(num, b));
    }
    
    //the short division principle
    public static String baseString(int num,int b){
        //digitChar.charAt(digit) is the character that represents the digit , 0 <= digit <= 15
        String digitChar = "0123456789ABCDEF",numStr = "";
        
        //stack holds the base-b digits of num
        ALStack<Character> stk = new ALStack<Character>();
        
        do{
            //push right-most digit on the stack
            stk.push(digitChar.charAt(num % b));
            
            //remove right-most digit form num
            num /= b;
            
        }while(num != 0);
        
        while(!stk.isEmpty()){
            
            //pop stack and add digit on top of stack to numStr
            numStr += stk.pop().charValue();
        }
        
        return numStr;
    }
}

　　　　实现demo，its a bit easy ，right?

　　　　　　

　　　　　　　//push right-most digit on the stack
            stk.push(digitChar.charAt(num % b));
            
            //remove right-most digit form num
            num /= b;