import java.math.BigDecimal;
public class T {
 public static void main(String[] args) {
 String a = "9999.9999";
 int b = 9999;
 double c = 9999.9999;
 char d = 99;
 System.out.println("===================");
 // 不同类型转为BigDecimal
 BigDecimal ma = new BigDecimal(a);
 BigDecimal mb = new BigDecimal(b);
 BigDecimal mc = new BigDecimal(c);
 BigDecimal md = new BigDecimal(d);
 System.out.println("ma:"+ma.toString());
 System.out.println("mb:"+mb.toString());
 System.out.println("mc:"+mc.toString());
 System.out.println("md:"+md.toString());
 System.out.println("===================");
 // 加
 BigDecimal add = ma.add(mb);
 System.out.println("加法："+add);
 // 减
 BigDecimal sub = ma.subtract(mb);
 System.out.println("减法："+sub);
 // 乘
 BigDecimal mul = mb.multiply(md);
 System.out.println("乘法："+mul);
 // 除
 BigDecimal div = mb.divide(md);
 System.out.println("除法："+div);
 System.out.println("===================");
 mc = mc.setScale(2, BigDecimal.ROUND_HALF_UP);
 System.out.println("四舍五入："+mc);
 System.out.println("===================");
 mc = mc.negate();
 System.out.println("负数："+mc);
 System.out.println("===================");
 }
}