使用会员卡消费算法

代码：

package com.pan.domain;

import java.text.DecimalFormat;
import java.text.ParseException;

public class AverageCalc {

	/**
	 * @param args
	 * @throws ParseException 
	 */
	public static void main(String[] args) throws ParseException {

		//总金额 500
		//本金 600.6
		//赠送金额 300.5
		
		double a=600.6d;
		double b=100.5d;
		double sum=a+b;
		
		double temp1=a/sum;
		double temp2=b/sum;
		
		System.out.println(temp1);
		System.out.println(temp2);
		
		System.out.println("比例：");
		int percent1=(int)(temp1*100);
		int percent2=(int)(temp2*100);
		System.out.println(percent1+"% - "+percent2+"%");
		
		double value1=500*temp1;
		double value2=500*temp2;
		
		System.out.println("结果：");
		System.out.println(value1+" - "+value2);
		
		DecimalFormat format=new DecimalFormat("#.00");
		System.out.println("保留两位小数");
		System.out.println(format.format(value1)+" - "+format.format(value2));
		value1=Double.parseDouble(format.format(value1));
		value2=Double.parseDouble(format.format(value2));
		System.out.println("误差：");
		System.out.println(500-(value1+value2));
		
		Double ad=0d;
		Double bd=0d;
		System.out.println(ad.equals(bd));
	}

}

0.8566538296961917
0.1433461703038083
比例：
85% - 14%
结果：
428.3269148480959 - 71.67308515190415
保留两位小数
428.33 - 71.67
误差：
0.0
true