如何從通用型返回一個字符串

-2

當然，因爲回報是字符串類型的，我不能返回一個空的結果，但我也可以一個字符串變量並不適用於它，然後傳遞經過的結果，所以我怎樣才能返回我的while循環的結果作爲一個字符串？我試着將字符串變量，這顯然不工作，然後創建字符串變量，然後將它們串聯到root.inorder的東西，但不會因爲操作數+的工作。如何從通用型返回一個字符串

public String toString() { 

    ArrayIterator<T> iter = new ArrayIterator<T>(); 

    String result = ""; 

    while (iter.hasNext()) 
     root.inorder(iter); 

    return null;   
} 

package javafoundations; 


public class Project10 { 

private static LinkedBinaryTree<Integer> tree; 

    public static void main (String[] args) { 

     LinkedBinaryTree<Integer> n2, n3, n4, n5, n6, n7, n8 ,n9, n10, n11, n12, n13; 

     Integer e1 = 10; 
     Integer e2 = 6; 
     Integer e3 = 19; 
     Integer e4 = 4; 
     Integer e5 = 8; 
     Integer e6 = 16; 
     Integer e7 = 20; 
     Integer e8 = 3; 
     Integer e9 = 5; 
     Integer e10 = 7; 
     Integer e11 = 9; 
     Integer e12 = 15; 
     Integer e13 = 17; 

     n8 = new LinkedBinaryTree<Integer>(e8); 
     n9 = new LinkedBinaryTree<Integer>(e9); 
     n4 = new LinkedBinaryTree<Integer>(e4, n8, n9); 

     n10 = new LinkedBinaryTree<Integer>(e10); 
     n11 = new LinkedBinaryTree<Integer>(e11); 
     n5 = new LinkedBinaryTree<Integer>(e5, n10, n11); 

     n12 = new LinkedBinaryTree<Integer>(e12); 
     n13 = new LinkedBinaryTree<Integer>(e13); 
     n6 = new LinkedBinaryTree<Integer>(e6, n12, n13); 

     n7 = new LinkedBinaryTree<Integer>(e7); 

     n3 = new LinkedBinaryTree<Integer>(e3, n6, n7); 
     n2 = new LinkedBinaryTree<Integer>(e2, n4, n5); 

     tree = new LinkedBinaryTree<Integer>(e1, n2, n3); 

     System.out.println("find: " + tree.find(e13)); 
     System.out.println("Contains: " + tree.contains(e1)); 
     System.out.println("empty?: " + tree.isEmpty()); 
     System.out.println("size: " + tree.size()); 
     System.out.println("getRoot: " + tree.getRootElement()); 

     System.out.println(tree); 
     System.out.println(tree.getLeft()); 
     System.out.println(tree.getLeft().toString()); 
     System.out.println(tree.levelorder()); 
     System.out.println(tree.inorder()); 
     System.out.println(tree.preorder()); 
     System.out.println(tree.postorder()); 




     /*StudentRecord<String, String> student1 = new StudentRecord<String, String>("Mike Litoris", 1235, "Sophomore \n"); 
     StudentRecord<String, String> student2 = new StudentRecord<String, String>("Graham Swallows", 1236, "Freshman\n"); 
     StudentRecord<String, String> student3 = new StudentRecord<String, String>("Gift Sales", 1237, "Senior\n"); 
     StudentRecord<String, String> student4 = new StudentRecord<String, String>("Chew Kok", 1238, "Junior\n"); 
     StudentRecord<String, String> student5 = new StudentRecord<String, String>("Bob Dylan", 5678, "Senior\n"); 

     BTNode<StudentRecord<String, String>> student = new BTNode<StudentRecord<String, String>>(student1); 


     student.setLeft(student1);*/ 

    } 
}

來源

2012-04-18 Tigh

我不知道我理解你的問題。你定義了某種參數化的容器，並且想爲該容器實現toString（）嗎？ – 2012-04-18 23:21:41

我有了加載對象樹司機和這的toString需要打印那些拿出來給我 – Tigh 2012-04-18 23:36:13

所以，如果我理解你：這是你自己的T'，這也定義了'容器'的toString（）'方法類'ArrayIterator '。你想'的toString（）'到容器（看起來像一棵樹）的全部內容的格式，但不知道如何聚合所有的字符串化的內容在一個地方以正確的順序。我對麼？ – 2012-04-18 23:42:46

出了什麼問題只是在做

public String toString() { 

    ArrayIterator<T> iter = new ArrayIterator<T>(); 

    String result = ""; 

    while (iter.hasNext()) 
     result += root.inorder(iter).toString(); 

    return result;   
}

假設root.inorder(iter)回報T。

來源

2012-04-19 00:08:37 trutheality

如何從通用型返回一個字符串

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