Java初学数组练习题

1.需求说明：有一个存储手机名称的数组，数据如下：String[] phones = {"null","iPhone4革新","iPhone4变化不大","iPhone5销量好","null","iPhone6高大上"};

要求：删除“iPhone5销量好”的元素，删除后把后面的数据依次往前推。

        String[] phones = {"null","iPhone4革新","iPhone4变化不大","iPhone5销量好","null","iPhone6高大上"};
        int count = 0;
        for (int i = 0; i < phones.length; i++) {
            if (phones[i]=="iPhone5销量好"){
                count++;
            }
            if (count==1){
                for (int j = i; j < phones.length-1; j++) {
                    phones[j] = phones[j+1];
                }
                break;
            }
        }
        String[] new_phones = new String[phones.length-1];
        for (int i = 0; i < phones.length-1; i++) {
            new_phones[i] = phones[i];
        }
        phones = new_phones;
        System.out.println(Arrays.toString(phones));

2.使用Arrays工具类来实现如下功能；需求：①：将一组乱序的字符进行排序；②：进行升序和逆序输出。

        char[] arr = {'a','c','u','b','e','p','f','z'};
        Arrays.sort(arr);
        System.out.println("升序排序："+Arrays.toString(arr));
        System.out.print("逆序排序为：");
        for (int i = arr.length-1; i >= 0; i--) {
            System.out.print(arr[i]+"  ");
        }

3.统计一个数组当中重复的元素个数，重复的元素分别是谁，重复元素的重复了多少次

数组int[] arr = {20,10,10,30,15,30,100,100,20,0,30,15,0,0,100,100,50,50}

        int[] arr = {20,10,10,30,15,30,100,100,20,0,30,15,0,0,100,100,50,50};
        Arrays.sort(arr);
        for (int i = 0; i < arr.length; i++) {
            int count = 0;
            int repeat = -1;
            for (int j = 0; j < arr.length; j++) {
                if (arr[i] == arr[j]){
                    count++;
                    repeat = j;
                }
            }
            i = repeat;
            if (count>1){
                System.out.println("重复的元素有："+arr[i]+"   重复了"+count+"次");
            }
        }