（1）今天做了什么； （2）明天准备做什么？ （3）遇到的问题，如何解决？
今天学习了菜鸟教程Java实例，数组
1.数组的排序和元素的查找——sort和binarySearch方法
import java.util.Arrays; public class Main
{
public static void main(String[] args)
{
int array[] = { 2, 5, -2, 6, -3, 8, 0, -7, -9, 4 };
Arrays.sort(array);
printArray("数组排序结果为",array);
int index = Arrays.binarySearch(array,2);
System.out.println("元素 2 在第 "+ index +" 个位置");
}
public static void printArray(String message,int[] array)
{
System.out.println(message + ": [length: " + array.length + "]");
for(int i = 0; i < array.length; i++)
{
if(i != 0)
{
System.out.print(",");
}
System.out.print(array[i]);
}
System.out.println();
}
}
2.数组添加元素
import java.util.Arrays; public class Main
{
public static void main(String[] args)
{
int array[] = { 2, 5, -2, 6, -3, 8, 0, -7, -9, 4 };
Arrays.sort(array);
printArray("数组排序",array);
int index = Arrays.binarySearch(array, 1);
System.out.println("元素 1 所在位置（负数为不存在）：" + index);
int newIndex = -index - 1;
array = insertElement(array,1,newIndex);
printArray("数组添加元素 1 后",array);
}
private static void printArray(String message,int[] array)
{
System.out.println(message + "[length: " +array.length+"]");
for(int i = 0; i < array.length; i++)
{
if(i != 0)
System.out.print(",");
System.out.print(array[i]);
}
System.out.println();
}
private static int[] insertElement(int []original,int element,int index)
{
int length = original.length;
int[] destination = new int[length + 1];
System.arraycopy(original, 0, destination, 0, index);
destination[index] = element;
System.arraycopy(original, index, destination, index+1, length - index);
return destination;
}
}
3.获取数组长度——length方法
public class Main {
public static void main(String args[]) {
String[][] data = new String[2][5];
System.out.println("第一维数组长度: " + data.length);
System.out.println("第二维数组长度: " + data[0].length);
}
}
4.数组反转
5.数组输出
public class Welcome {
public static void main(String[] args){
String[] runoobs = new String[3];
runoobs[0] = "菜鸟教程";
runoobs[1] = "菜鸟工具";
runoobs[2] = "菜鸟笔记";
for (int i = 0; i < runoobs.length; i++){
System.out.println(runoobs[i]);
}
}
}
6.数组获取最大和最小值
