找错（菜鸟问题）

如题

package university.deparment.biology.students.book;

import java.util.Scanner;

public class Consumption {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("请输入金额");
boolean flag = true;
double money = input.nextDouble();
System.out.println("是否参加优惠换购活动");
System.out.println("1：满五十元加两元参加换购百事可乐一瓶");
System.out.println("2：满一百元加三元换500ml可乐一瓶");
System.out.println("3：满一百元加十元换购一百斤面粉");
System.out.println("4：满一百元加十元换购一个苏泊尔锅");
System.out.println("5：满200元加二十元可换购欧莱雅爽肤水一瓶");
System.out.println("0：不换购");
String result="";
System.out.println("请选择：");
int i= input.nextInt();
if (i<50) {
flag = false;
}else{
switch (i) {
case 1:
result = "百事可乐一瓶";
money+=2 ;
break;
case 2:
if (i<100) {
flag = false;
}
result="500ml可乐一瓶";
money+=3;
break;
case 3:
if (i<100) {
flag = false;
}
result= "5公斤面粉";
money+=10;
break;
case 4:
if (i<200) {
flag = false;
}
result="一个苏泊尔炒菜锅";
money+=10;
break;
case 5:
if (i<200) {
flag = false;
}
result="欧莱雅爽肤水一瓶";
money+=20;
break;

default:
flag = false;
break;
}
}
System.out.println("本次消费金额："+money);
if (flag) {
System.out.println("成功换购"+result);
}else{
System.out.println("换购失败");
}
}
}
运行结果总是：换购失败
[解决办法]
1.你判断的地方写错了，应该用 if(money < 100)，不应该用i
2.if判断里面最好写break,不然它还会走result= "5公斤面粉";money+=10;
虽然你这个不会错，但有隐患。
[解决办法]
你的代码没格式不好看，写了一个，你看看吧

package com.study.test;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.Map.Entry;

public class Test {

private static Map<Integer, Domain> map = new LinkedHashMap<Integer, Domain>();

static{
map.put(1, new Domain(2, 50, "满50元，加2元参加换购百事可乐1瓶", "百事可乐1瓶"));
map.put(2, new Domain(3, 100, "满100元，加3元换500ml可乐1瓶", "500ml可乐1瓶"));
map.put(3, new Domain(10, 100, "满100元，加10元换购5公斤面粉", "5公斤面粉"));
map.put(4, new Domain(10, 200, "满200元，加10元换购1个苏泊尔锅", "苏泊尔锅1个"));
map.put(5, new Domain(20, 200, "满200元，加20元可换购欧莱雅爽肤水1瓶", "欧莱雅爽肤水1瓶"));
map.put(0, new Domain(0, 0, "不换购", ""));
}

public static void main(String[] args){
double money = 0.0;
while(true){
Scanner input = new Scanner(System.in);
System.out.println("请输入金额");
try {
money = input.nextDouble();
break;
} catch (Exception e) {
System.out.println("输入的金额有误，请重新输入！！");
}
} 
 
Set<Entry<Integer, Domain>> entrys = map.entrySet();
Iterator<Entry<Integer, Domain>> iter = entrys.iterator();
while(iter.hasNext()){
Entry<Integer, Domain> entry = iter.next();
System.out.println(entry.getKey() + ": " + entry.getValue());
}
System.out.println("请选择：");
Domain domain = null;
while(true){
try {
Scanner input = new Scanner(System.in);
int type = input.nextInt();
domain = map.get(type);
if(domain != null){
break;
}else{
System.out.println("选择的方式不存在，请重新输入！！");
}
} catch (Exception e) {
System.out.println("输入的兑换方式有误，请重新输入！！");
}
}
double addmoney = domain.getPrice();
System.out.println(money + addmoney);
if(addmoney > 0){
System.out.println("成功换购：" + domain.getValue());
}else{
System.out.println("没参加换购活动。");
}
}



}

class Domain{
private double price;
private double over;
private String name;
private String value;

public Domain(double price, double over, String name, String value){
this.price = price;
this.over = over;
this.name = name;
this.value = value;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}

public double getOver() {
return over;
}
public void setOver(double over) {
this.over = over;
}

public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
public String toString(){
return name;
}

}