存儲布爾值

Question

我有問題如何更改給定類的布爾值，以便一旦它再次遇到它有最後一次設置的值。這是我的課

public class Sandwich { 
    private String type; 
    private double price; 
    private String ing; 
    public boolean owned; 

    Sandwich (String t, double p, boolean o){ 
     type = t; 
     price = p; 
     owned = o; 
    } 

    public boolean getO(){ 
     return this.owned; 
    } 

    public void setO(boolean o){ 
     this.owned = o; 
    } 

    public String getType(){ 
     return this.type; 
    } 
} 

，並在那裏訪問，應該改變的地方：

public void purchase(Sandwich s) { 
    boolean owned = s.owned; 

    //I tried also with accessor and mutator here but then changed to public 
    String type = s.getType(); 
    if (owned == false) { 
     if (money <= 0){ 
      System.out.println("Worker " + this.name + " can not buy " + type + " sandwich, cuz he doesn't have enough money"); 
     } else { 
      System.out.println("Worker " + this.name + " can buy " + type + " sandwich"); 
      this.money = money; 
      owned = true; 

      //this is the place where it is supposed to change value to true (sandwich was bought and has owner now 
      s.owned = owned; 
     } 
    } else if (owned == true) { 
     System.out.println("Worker " + this.name + " can not buy " + type + " sandwich cuz it was bought"); 
     System.out.println("Test"); 
    } 
} 

問題是，雖然給定的三明治是在過去購買了國有值設置爲每次假我嘗試運行此代碼。我需要三明治來記錄擁有的改變後的價值，以便下次我運行該條件時將擁有== true。它怎麼可能

Answer 1

似乎是在你的設計中的缺陷所取代。您需要在Worker和sandwish類型之間建立關係。

你可以做的只是在工人類中實施購買的sandwish類型列表，並在工人購買sandwish時與其進行比較。

或者如果你想，你可以有一個布爾值的所有sandwish類型的散列表，表明類型是否已經被購買或沒有。

Answer 2

你創建了get和set例程，然後沒有使用它們。我會將代碼更改爲此。

public void purchase(Sandwich s){ 
      String type = s.getType(); 
      if (!(s.getO())){ 
       if (money <= 0){ 
        System.out.println("Worker " + this.name + " can not buy " + type + " sandwich, cuz he doesn't have eno 

ugh money"); 
       } else { 
        System.out.println("Worker " + this.name + " can buy " + type + " sandwich"); 
        this.money = money; 
        s.setO(true); 
       } 
      } else { 
       System.out.println("Worker " + this.name + " can not buy " + type + " sandwich cuz it was bought"); 
       System.out.println("Test"); 
      } 
    } 

Answer 3

只是刪除

boolean owned = s.owned; 

，並使用s.getO()，你必須使用owned

例如

if (owned == false){ 

可以

if (!s.getO()){ 

，並使用setter方法s.setO(true/false)去改變它。

例如

owned = true; 
s.owned = owned; 

可以通過

s.setO(true);