Java案例——多人投票

public class Test2 {
    public static void main(String[] args) {
        Random r = new Random();
        // 选择
        String[] ele = {"A","B","C","D","AB","AC","AD","ABC","ABD","ACD","ABCD","BC","BD","BCD","CD"};
        // 姓名
        String[] names = createNames();
        printArr(names);
        // 1 要求程序记录每个学生的选择情况
        // 使用一个Map集合存储
        Map<String , String> data = new TreeMap<>();

        // 把学生选择的数据存入进去
        for (int i = 0; i < names.length; i++) {
            String se = ele[r.nextInt(ele.length)];
            data.put(names[i],se);
        }
        // 选择数量存储
        Map<Character,Integer> infos = new HashMap<>();
        // 遍历
        Collection<String> values = data.values();
        // 遍历所有姓名的选择
        for (String value : values) {
            // 遍历所有选择的内容
            for (String s : values) {
                System.out.print(s+"\t");
                for (int i = 0 ; i < s.length();i++){
                    char ch = s.charAt(i);
                    if (infos.containsKey(ch)){
                        infos.put(ch,infos.get(ch)+1);
                    }
                    else {
                        infos.put(ch,1);
                    }
                }
            }
        }
        System.out.println();
        System.out.println(infos);
    }

    /**
     * 创建姓名数组
     * @return  数组
     */
    public static String[] createNames(){
        String[] names = new String[3];
        for (int i = 0; i < names.length ; i++) {
            names[i] =  (i+1)+"号";
        }
        return names;
    }

    /**
     * 打印数组内容
     * @param arr
     */
    public static void printArr(String[] arr){
        StringBuilder sb = new StringBuilder('[');
        for (int i = 0; i < arr.length; i++) {
            sb.append(arr[i]);
        }
        sb.append(']');
        System.out.println(sb);
    }
}