数组练习

计算全班学员的平均分

方法一

     int[] a = {60, 70, 80, 90};
        int b = 0;
        int s = 0;
        for (int i = 0; i < a.length; i++) {
            b = a[i];
            s += a[i];
            System.out.println(b);
        }

        System.out.println("平均成绩是：" + s / a.length);

方法二

  Scanner scanner = new Scanner(System.in);
        double[] a = new double[5];
        double d=0;
        for (int i = 0;i<a.length;i++){
            System.out.println("输入成绩");
            double g=scanner .nextInt();
            a[i]=g;
            d+=a[i];
        }
        System.out.println("平均分是"+d/a.length);

有一个数列：8，4，2，1，23，344，12 循环输出数列的值,求数列中所有数值的和猜数游戏：从键盘中任意输入一个数据，判断数列中是否包含此数

 Scanner scanner = new Scanner(System.in);
  int[] a = {8, 4, 2, 1, 23, 344, 12};
        int b = 0;
        System.out.println("输入一个数");
        int c = scanner.nextInt();
        int i;
        for (i = 0; i < a.length; i++) {
            b += a[i];
            if (c == a[i]) {
                System.out.println("包含");
                break;
            }
        }
        if (i == a.length) {
            System.out.println("不包含");
        }
        System.out.println(b);

从键盘输入本次Java考试五位学生的成绩，求考试成绩最高分

   Scanner scanner = new Scanner(System.in);
  int[] a = new int[5];
        int max = 0;
        int i;
        for (i = 0; i < a.length; i++) {
            System.out.println("输入成绩");
            int g = scanner.nextInt();
            a[i] = g;
            if (max <= a[i]) {
                max = a[i];
            }
        }
        System.out.println("最大成绩是" + max);

有一组学员的成绩{50，90，70，80}，将它们按升序排列。要增加一个学员的成绩，将它插入成绩序列，并保持升序。

int[] a = {50, 90, 70, 80};
        Arrays.sort(a);
        System.out.println("数");
        int b = scanner.nextInt();
        int c = 0;
        for (int i = 0; i < a.length; i++) {
            if (b <= a[i]) {
                c = i;
                break;
            }
        }
        int[] d = new int[5];
      //插入第一步  for (int i = 0; i < c; i++) {
            d[i] = a[i];
        }
     //第二部   d[c] = b;
       //第三部 for (int i = c + 1; i < d.length; i++) {
            d[i] = a[i - 1];
        }
       //遍历 for (int i = 0; i < d.length; i++) {
            System.out.println(d[i]);
        }

将 一组乱序的字符进行排序 进行升序和逆序输出

       char[] a={'s','d','b','h'};
                Arrays.sort(a);
        for (int i = 0;i<a.length;i++){
            System.out.println(a[i]);
        }
                for (int i = a.length-1;i>=0;i--){
                     System.out.print(a[i]);
        }

定义一个字符串数组，查找某个字符串在数组中出现的次数

  Scanner scanner = new Scanner(System.in);
  String[] a = {"ww", "dd", "ww", "aa", "dd", "ww"};
        int c = 0;
        System.out.println("输入字符串");
        String b = scanner.next();
        for (int i = 0; i < a.length; i++) {

            if (b.equals(a[i])) {
                c++;
            }

        }
        System.out.println(b + "出现" + c + "次");