《Cracking the Coding Interview》——第14章：Java——题目4

2014-04-26 19:02

题目：解释下C++里模板和java里泛型的区别？

解法：我很少用java，属于连语法都不过关的程度。所以这个题还真没法详细答，查了些资料以后写了以下几点。

代码：

 1 // 14.4 tell me about the differences between C++ template and java generics.

 2 // Answer:

 3 //    1. C++ template can be used on built-in type and user-defined types, java generics can only be used on classes. Integer for int, Double for double.

 4 //    2. java generics can put some restrictions on the <T>, such as <T extends superclass>, whereas this is not practical in C++.

 5 //    3. You may use downcast instead of generics, but generics enhance the resuability of code, so is template in C++.

 6 import java.util.Vector;

 7 

 8 public class TestJava<T> {

 9     public T data;

10 

11     public TestJava(T data) {

12         // TODO Auto-generated constructor stub

13         this.data = data;

14     }

15 

16     String getType() {

17         return this.data.getClass().getName();

18     }

19 

20     public static void main(String[] args) {

21         Vector<Integer> v = new Vector<Integer>();

22         v.add(2);

23         v.add(1);

24 

25         TestJava<Vector<Integer>> testJava = new TestJava<Vector<Integer>>(v);

26         System.out.println(testJava.getType());

27         System.out.println(v);

28     }

29 }