如何創建一個類的兩個實體，從該類更新同一個陣列？就像這里一樣，我希望 r1 和 r2 更新相同的pendingOrders，所以最后陣列是['yo','lo']。這沒有發生， r1 和 r2 正在制作不同的陣列。
import java.util.ArrayList;
public class Student{
static int enrollmentNumber;
String studentName;
Student(String name){
enrollmentNumber = 1;
studentName = name;
}
public String toString(){
return enrollmentNumber ": " this.studentName;
}
public static void main(String[] args) {
Student s = new Student("Pam");
System.out.println(s.toString());
Student s1 = new Student("Hellooo");
System.out.println(s1.toString());
Student s2 = new Student("Pam2");
System.out.println(s2.toString());
Robot r1 = new Robot("Bob");
r1.addToQueue("yo");
System.out.println(r1.returnList()); // prints: ['yo']
Robot r2 = new Robot("Rob");
r2.addToQueue("lo");
System.out.println(r2.returnList()); // prints: ['lo']
// But I want it to print ['yo', 'lo']
}
}
class Robot{
public ArrayList<String> pendingOrders = new ArrayList<String>();
String rName;
Robot(String name){
rName = name;
}
public void addToQueue(String s){
pendingOrders.add(s);
}
public ArrayList returnList(){
return pendingOrders;
}
}
uj5u.com熱心網友回復：
將static關鍵字添加到pendingOrdersin Robot。
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