java头歌-数组进阶

第一关

public static void main(String[] args) { //动态构建arr1 int[] arr1 = new int[3]; Scanner sc = new Scanner(System.in); for(int i = 0 ; i< arr1.length ; i++){ arr1[i] = sc.nextInt(); } /********** Begin **********/ //创建数组arr2 int[] arr2 = new int[3]; for (int i = 0; i < arr1.length; i++) { arr2[i] = arr1[i]; } //使用for循环将arr1的数据复制给arr2 //输出arr2 for (int i = 0; i < arr2.length; i++) { System.out.println(arr2[i]); } /********** End **********/ }

第二关

public static void main(String[] args) { Scanner sc = new Scanner(System.in); //str为要查找的字符串 String str = sc.next(); /********** Begin **********/ //创建数组 arr 给数组赋值 {"张三","张三丰","张无忌","王二麻子","张富贵"} String arr[] = new String[]{"张三","张三丰","张无忌","王二麻子","张富贵"}; for (int i = 0; i < arr.length; i++) { if (str.equals(arr[i])) { System.out.println(str + "在数组的第"+(i+1)+"个位置"); } } /********** End **********/ }

第三关

public static void main(String[] args) { Scanner sc = new Scanner(System.in); int a = sc.nextInt(); int b = sc.nextInt(); /********** Begin **********/ //将a的值赋给b b的值赋给a int temp = a; a = b; b = temp; /********** End **********/ System.out.println(a); System.out.println(b); }

第四关

选择排序

public static void main(String[] args) { Scanner sc = new Scanner(System.in); //动态创建数组 int[] arr = new int[sc.nextInt()]; for (int i = 0; i < arr.length; i++) { arr[i] = sc.nextInt(); } /********** Begin **********/ int temp =0; for (int i = 0; i < arr.length; i++) { int min = i; for (int j = i; j < arr.length; j++) { if (arr[j] >= arr[min]) { min = j; /********** End **********/ } } temp = arr[min]; arr[min] = arr[i]; arr[i] = temp; } System.out.println(Arrays.toString(arr)); }

第五关

冒泡

public static void main(String[] args) { Scanner sc = new Scanner(System.in); //动态创建数组 int[] arr = new int[sc.nextInt()]; for(int i = 0 ; i< arr.length ; i++){ arr[i] = sc.nextInt(); } /********** Begin **********/ for(int i = 0;i<arr.length;i++) { for (int j = 0; j < arr.length; j++) { if (arr[i] < arr[j]) { int temp = arr[i]; arr[i] = arr[j]; arr[j] = temp; } } /********** End **********/ } System.out.println(Arrays.toString(arr)); }