poj1001Exponentiation

poj1001Exponentiation

大说乘法运算，Java中有BigDecimal类支持，关键是格式要求。java中应该有专门处理格式的类吧，不过我这里用的是最原始的格式处理方式——字符串拆分。

import  java.io. * ;
import  java.util. * ;
import  java.math. * ;
class  Main
{
    public static void main(String[] args)
    {
        int p;
        BigDecimal dc;
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext())
        {
            dc = sc.nextBigDecimal();
            p = sc.nextInt();
            
            dc = dc.pow(p);
            String strdc[] = dc.toString().split("E-");
            
            StringBuffer strbf = new StringBuffer();
            if(strdc.length == 2)
            {
                strbf.append(".");
                char[] charAry = strdc[0].toString().toCharArray();
                
                int zeros = new Integer(strdc[1]);
                
                for(int i = 1; i < zeros; i++)
                {
                    strbf.append("0");
                }
                strbf.append(charAry[0]);

                if(!strdc[0].equals("1"))
                {
                    strbf.append(strdc[0].toString().toCharArray(), 
                        2, strdc[0].toString().toCharArray().length - 2);
                }
                
            }
            else
            {
                strbf.append(dc);
            }
            
            int i = strbf.length() - 1;
            while(strbf.charAt(i) == '0')
                i--;
            if(strbf.charAt(i) == '.')
                i--;
            String rs = new String(strbf.toString().toCharArray(), 0, i + 1);
            System.out.println(rs);
        }
    }
}