一维数组

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1	写一段程序来阐述数组简单的应用

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package com.liaojianya.chapter1;   import java.util.Random;   /**  * This program demonstrates the use of array.  * @author LIAO JIANYA  * 2016年7月20日  */ public class ArrayAssignment8_3 {     public static void main(String[] args)     {         Random rand = new Random();         int[] a = null;         int[] b = null;         a = new int[rand.nextInt(10) + 1];         b = a;                   System.out.println("the length of array_a : " + a.length);         System.out.println("the length of array_b : " + b.length + "\n");                   for(int i = 0; i < a.length; i++)         {             a[i] = rand.nextInt(100);             System.out.print("a[" + i + "] = " + a[i] + "\t");             System.out.println("b[" + i + "] = " + b[i]);         }                   if(a.length == 1)         {             System.out.println("The array_a only has one element.\n"                     + "So the max value of array_a is same as the min value!");         }         else         {             int max = a[0];             int min = a[0];                                         for(int i = 0; i < a.length; i++)             {                 if(a[i] > max)                 {                     max = a[i];                 }                                   else if(a[i] < min)                 {                     min = a[i];                 }             }                           System.out.println("\nThe max value of array_a is : " + max);             System.out.println("The min value of array_a is : " + min);                       }                 } }

　　运行结果1：

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the length of array_a : 1 the length of array_b : 1   a[0] = 70   b[0] = 70 The array_a only has one element. So the max value of array_a is same as the min value!

　　运行结果2：

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the length of array_a : 7 the length of array_b : 7   a[0] = 39   b[0] = 39 a[1] = 90   b[1] = 90 a[2] = 49   b[2] = 49 a[3] = 35   b[3] = 35 a[4] = 33   b[4] = 33 a[5] = 12   b[5] = 12 a[6] = 75   b[6] = 75   The max value of array_a is : 90 The min value of array_a is : 12

　　分析：

　　1）代码行：b = a；表示将a数组的引用赋值给数组b，这时a和b是指向同一个数组对象。即“一个数组，两个名字”

　　2）创建一个Random类型的对象rand，此对象可以灵活的产生随机数，代码行a = new int[rand.nextInt(10)+1]; 在rand.nextInt（）后加1，可以避免出现0个元素数组。

若不加1，若随机到0，则会显示：

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the length of array_a : 0 Exception in thread "main" the length of array_b : 0   java.lang.ArrayIndexOutOfBoundsException: 0     at com.liaojianya.chapter1.ArrayAssignment8_3.main(ArrayAssignment8_3.java:30)

　　3）将变量min与max初值设为数组的第一个元素后，再逐一的与数组中的各元素相比，比min小的就将该元素值赋给min存放，使得min中的值始终保持最小；同理，当该元素大于max时，就将该元素赋给max存放，使得max的值保持最大。