java - 在java泛型方法中发送数组作为参数

Question

class MaximumTest {
    // determines the largest of three Comparable objects
    public static <T extends Comparable<T>> int CountDuplicates(T[] anArray, T elem) {
        int count = 0;
        for (T e: anArray)
            if (e.compareTo(elem) == 0)
            ++count;
        return count;
    }
    public static void main(String args[]) {
        double[] D_arr = {
            1.2, 3.4, 0.0, 4.5, 0.0
        };
        int[] I_arr = {
            0, 0, 0, 0, 1, 3, 5
        };
        System.out.println("No of zeros in Double Array = " + CountDuplicates(D_arr, 0.0));
        System.out.println("No of zeros in Double Array = " + CountDuplicates(I_arr, 0));
    }
}

这段代码有什么错误？

Answer 1

您的数组应该是引用类型:

Double[] D_arr = {1.2, 3.4, 0.0, 4.5, 0.0};
Integer[] I_arr = {0,0,0,0,1,3,5};

原始类型不能用作泛型类型。

进行此更改后，您的代码将通过编译并生成输出:

No of zeros in Double Array = 2
No of zeros in Double Array = 4