[英]adding an object into an array list using stack in java
In this code I tried to add a new order into the array list using stack since i'm not allowed to use add(), but when I try to call it the program shows an error saying that the push() method was not found, it be great if someone could tell me where I went wrong in the code 在此代码中,由于不允许使用add(),我尝试使用堆栈将新顺序添加到数组列表中,但是当我尝试调用它时,程序显示错误,提示未找到push()方法,如果有人能告诉我代码中哪里出了问题,那是很棒的
import java.util.ArrayList;
import java.util.Scanner;
public class OrderArrayList {
ArrayList<OrderList> orderList;
public OrderArrayList() {
orderList = new ArrayList();
}
public boolean isEmpty() {
return orderList.isEmpty();
}
public void push(OrderList x) {
orderList.add(x);
}
public void addOrder() {
Scanner input1 = new Scanner(System.in);
System.out.print("Product code: ");
String pcode = input1.nextLine();
Scanner input2 = new Scanner(System.in);
System.out.print("Customer Code: ");
String ccode = input2.nextLine();
Scanner input3 = new Scanner(System.in);
System.out.print("Quantity: ");
int quantity = input3.nextInt();
OrderList order = new OrderList(pcode, ccode, quantity);
orderList.push(order);
}
Isn't the whole point to "hide" the ArrayList
? 并不是全部要“隐藏”
ArrayList
吗? That is why you added a push()
function? 这就是为什么您添加了
push()
函数?
So orderList.push(order);
所以
orderList.push(order);
should be push(order);
应该是
push(order);
. 。
orderList.push(order);
orderList is ref of ArrayList and ArrayList class does not have push() method. orderList是ArrayList的引用,并且ArrayList类没有push()方法。 https://docs.oracle.com/javase/7/docs/api/java/util/ArrayList.html You should create an instance of your class "OrderArrayList" and call push() method on it.
https://docs.oracle.com/javase/7/docs/api/java/util/ArrayList.html您应该创建“ OrderArrayList”类的实例,并在其上调用push()方法。
OrderArrayList orderArrayList = new OrderArrayList();
...
...
//collect input from user
OrderList order = new OrderList(pcode, ccode, quantity);
orderArrayList.push(order);
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