Array using: reverse, tools, bubble sort

com.atguigu.exec Package;
/ *
 * array1 and array2 two variables declared in Mian () method, they int type array
 * initialize array1 as 2,3,5,7,11,13,17,19
 * Display content of array1
 * variable is equal to the assignment array2 array1, array2 modify the even-indexed elements to be equal to the index value and print array1
 relationship of * array1 and array2
 * modifications of the subject to achieve replication of array1 array2
 *
 * /
public class ArrayDome3 {
 public void main static (String [] args) {
  int [] array1, array2;
  
  array1 = new new int [] {2,3,5,7,11,13,17,19};
  for (int I = 0; I < array1.length; I ++) {
   System.out.println (array1 [I] + "\ T");
  }
  // assignment array2 array1 address variable equal to the value of the array rather than copy assignment
  array2 array1 =;
  / *
   * copy method
   * array2 = new int [array.length] ; // new array must be re new
   * for(int i = 0; i < array.length;i++){
   *   array2[i] = array1[i];
   * }
   *
   */
  for( int i = 0;i < array2.length;i++) {
   if(i % 2 == 0) {
    array2[i] = i;
   }
  }
  
  for(int i = 0;i <array1.length;i++) {
   System.out.println(array1[i]+"\t");
  }
  
 }
}

************************************************************************************************************************************

com.atguigu.exec Package;
/ *
 * reverse
 * /

public class ArrayDemo4 {
 public static void main(String[] args) {
  String [] arr = new String[] {"aa","bb","cc","dd","jj"};
  
  //方法一
  for(int i = 0;i < arr.length/2;i++) {
   String temp = arr[i];
   arr[i] = arr[arr.length-i-1];
   arr[arr.length-i-1] = temp;
  }
  
  //方法二
  for(int i = 0,j = arr.length-1;i < j;i++,j--) {
   String temp = arr[i];
   arr[i] = arr[j];
   arr[j] = temp;
  }
  
  //查找
  //线性查找
  boolean isFlag = true;
  String dest = "bb";
  for(int i = 0;i < arr.length;i++) {
   //判断字符是否相等:equals
   IF (dest.equals (ARR [I])) {
    System.out.println ( "find, position:" + I);
    isFlag = to false;
    BREAK;
   }
  }
  
  IF (isFlag) {
   System.out.println ( " not found ");
  }
 
  // binary search
  @ premise: the array must be ordered by looking
  int [] of arr1 = new new int [] {} 1,4,6,8,43,48,99,100;
  int = dest1 48;
  int head = 0;
  int = End-arr1.length. 1;
  Boolean = isFlag1 to true;
  
  the while (head <= End) {
   int = Middle (End + head) / 2;
   IF (== dest1 of arr1 [Middle]) {
    System.out.println ( "find, position" + Middle);
    isFlag1 = to false;
    BREAK;
   } the else IF (Middle <dest1) {
    head = middle + 1;
   }
   else {
    end = middle -1;
   }
  }
  if(isFlag1) {
   System.out.println("未找到");
  }  
 }
}

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package com.atguigu.java;

import java.util.Arrays;

/ *
 * Java.util.Arrays: array operation tools, many of which defines a method of operating an array
 *
 *
 * /

{class ArrayTest1 public
 public static void main (String [] args) {
  
  //1.boolean the equals (int [] A, int [] B) determines whether the same two arrays
  int [] arr1 = new int [ ] {1, } 2,3,4;
  int [] = arr2 is new new int [] {1,3,2,4};
  Boolean = isEquals that Arrays.equals (of arr1, arr2 is);
  System.out.println (isEquals);
  
  // 2 .String toString (int [] a) : the information output array
  System.out.println (of Arrays.toString (arr2 is));
  
  //3.void fill (int [] A, int Val): the specified value is filled into an array
  Arrays.fill (arr1,10);
  System.out.println (of Arrays.toString (of arr1));
  
  //4.void Sort (int [] A): sort the array
  Arrays.sort (arr2 is);
  the System.out .println (Arrays.toString (arr2));
  
  //5.int binarySearch(int[] a, int key)//二分查找
  int[] arr3 = new int[] {-98,-34,2,34,54,66,79,105,210,333};
  int index = Arrays.binarySearch(arr3, 79);
  if(index >= 0) {
   System.out.println(index);
  }else {
   System.out.println("未找到");
  }
 }
}

********************************************************************************************************************************

package com.atguigu.exec;

/*
 *数值型数组中元素、最大值、最小值、平均值、总和
 */
public class ArrayDemo2 {
 public static void main(String[] args) {
  int[] arr = new int[10];
  
  for(int i = 0;i < arr.length;i++) {
   arr[i] = (int)(Math.random()*(99-10+1)+10);
  }
  
  int maxValue = arr[0];
  for(int i = 1;i < arr.length;i++) {
   if(arr[i]>maxValue) {
    maxValue = arr[i];
   }
  }
  
  int minValue = arr[0];
  for(int i = 1;i < arr.length;i++) {
   if(arr[i] < minValue) {
    minValue = arr[i];
   }
  }
  
  int sum = 0;
  for(int i = 0;i < arr.length;i++) {
   sum += arr[i];
  }
  
  int avgValue = sum / arr.length;
  
 }
 

}

*****************************************************************************************************************************

package com.atguigu.java;
/*
 * 数组的冒泡排序
 */
public class BubbleSort {
 public static void main(String[] args) {
  
  int[] arr = new int[] {43,32,76,-98,0,64,33,11};
  for(int i = 0; i < arr.length - 1;i++) {
   for(int j = 0; j < arr.length -1-i;j++) {
    if(arr[j] > arr[j+1]) {
     int temp = arr[j];
     arr[j] = arr[j+1];
     arr[j+1] = temp;
    }   
   }   
  }
  for(int i = 0;i < arr.length;i++) {
   System.out.println(arr[i]);
  }
  
 }
}