我如何檢查點是否是Set上的成員？

Question

我有一個類Set，我應該從Set類兩點 用戶要求的閱讀。

我有一些問題的方法member和subset。

我沒有任何想法是如何工作的，所以如果任何一個可以給我說，我能理解這種方法是如何工作的例子？

class Set { 
    private point[] p; 

    public Set(int n) { 
     p = new point[n]; 
     readSet(n); 
    } 

    private void readSet(int n) { 
     System.out.println("Please enter " + n + " points"); 

     for (int i = 0; i < n; i++) { 
      int x = 0; 
      int y = 0; 

      p[i] = new point(x, y); 
     } 
    } 

    public void printSet() { 
     for (int i = 0; i < p.length; i++) { 
      System.out.print(p[i]); 
     } 
    } 

    public void shiftSet(int dx, int dy) { 
     for (int i = 0; i < p.length; i++) { 
      p[i].shift(dx, dy); 
     } 
    } 

    // returns if P is in the set, making use of the equals method in class Point 
    public boolean member(point P) { 
     for (int i = 0; i < p.length; i++) { 
      // ... 
     } 
     return true; 
    } 

    // returns if current set is a subset of S, making use of the member method 
    public boolean subset (Set S) { 
     // ... 
     return true; 
    } 
} 

Answer 1

這應該是它，我會解釋給你聽：

public boolean member(point P) { 
    // search for P in p 
    for (int i = 0; i < p.length; i++) { 
     // if it is contained 
     if (p[i].equals(P)) { 
      // here it is 
      return true; 
     } 
    } 

    // couldn't find P 
    return false; 
} 

public boolean subset(Set S) { 
    // check for every point in p 
    for (int i = 0; i < p.length; i++) { 
     // whether it is contained in S 
     if (!S.member(p[i])) { 
      // can't be a true subset 
      return false; 
     } 
    } 

    // everything is as expected 
    return true; 
}