Java练习——数组练习

一、求最值

public class Test1 {public static void main(String[] args) {int[] arr = {33,5,22,44,55};int max = arr[0];for (int i = 0; i < arr.length; i++) {if (max < arr[i]){max = arr[i];}}System.out.println(max);}
}

二、遍历数组求和

import java.util.Random;public class Test2 {public static void main(String[] args) {Random r = new Random();int[] arr = new int[10];int sum = 0;int max = 0;for(int i = 0; i < arr.length; i++){arr[i] = r.nextInt(10);}for(int i = 0; i < arr.length; i++){System.out.print(arr[i] + " ");}System.out.println();System.out.println("------------------");for(int i = 0; i < arr.length; i++){sum += arr[i];if(arr[i] > arr[0]){max = arr[i];}}int avg = sum/arr.length;for(int i = 0; i < arr.length; i++){if(arr[i] < avg){System.out.println("小于平均数的元素为：" + arr[i]);}}System.out.println("和为：" + sum);System.out.println("平均数为：" + sum/arr.length);System.out.println("最大值为：" + arr[0]);}
}

三、交换数据

public class Test3 {public static void main(String[] args) {int[] arr = { 1, 2, 3, 4, 5 };int temp = arr[0];for(int i = 0,j = arr.length - 1;i<j;i++,j--){temp = arr[i];arr[i] = arr[j];arr[j] = temp;}for (int i = 0; i < arr.length; i++) {System.out.println(arr[i]);}}
}

四、打乱数据

import java.util.Random;public class Test4 {public static void main(String[] args) {int[] arr = { 1, 2, 3, 4, 5 };Random r = new Random();for (int i = 0; i < arr.length; i++){int randomindex = r.nextInt(arr.length);int temp = arr[i];arr[i] = arr[randomindex];arr[randomindex] = temp;}}
}

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