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HashSet<Students> hashSet = new HashSet<>();
hashSet.add(zs);
boolean flag = hashSet.contains(zs1);
if (flag) {
for (Students students : hashSet) {
if (students.getId() == id) {
students.getNum ++; // 商品加1
}
}
}
伪代码,类似这种
public class Testa {
static HashSet<String> gds = new HashSet<String>();
public static void main(String[] args) {
// TODO Auto-generated method stub
int count=0;
Scanner sc = new Scanner(System.in);
String str;
while (count< 5) {
System.out.println("请输入商品的编号");
String number=sc.next();
System.out.println("请输入商品的名字");
String name=sc.next();
System.out.println("请输入商品的单价");
double unitprice=sc.nextDouble();
System.out.println("请输入商品的数量");
int quantity=sc.nextInt();
//判断商品是否已经存在
if((str=check(number))!=null) {
String[] s=str.split(",");
//移除原来的数据String
gds.remove(str);
//数量累加后生成新的String
str=number+","+name+","+unitprice+","+(Integer.valueOf(s[3])+quantity);
}else {
//新的String
str=number+","+name+","+unitprice+","+quantity;
}
gds.add(str);
count++;
}
System.out.println("总价:"+getSum());
}
public static String check(String str) {
String temp;
Iterator<String> it=gds.iterator();
while (it.hasNext()) {
temp=it.next();
String[] s=temp.split(",");
//判断是否存在商品编号,存在的话直接返回该String值
if(s[0].equals(str)) {
return temp;
}
}
return null;
}
public static double getSum() {
double sum=0;
Iterator<String> it=gds.iterator();
while(it.hasNext()) {
String[] s=it.next().split(",");
sum=sum+(Double.valueOf(s[2])*Integer.valueOf(s[3]));
}
return sum;
}
}
Set set = new HashSet();
set.add("1");
set.add("2");
set.add("3");
Iterator it = set.iterator();
while(it.hasNext()) {
System.out.println(it.next());
}