数组

package com.phone.week3.day1;

import java.util.Scanner;

public class Demo3 {

public static void main(String[] args) {    Scanner in = new Scanner(System.in);    double []prices = new double[5]; //声明一个浮点型的长度为5的数组    int len = prices.length;    for (int i = 0; i <len; i++) {        System.out.print("请输入第"+(i+1)+"笔购物金额:");        prices[i]=in.nextDouble(); //从键盘接收购物金额    }    double sum = 0; //求总金额的    System.out.println("序号\t金额(元)");    for (int i = 0; i < len; i++) {        System.out.println((i+1)+"\t"+prices[i]);        sum+=prices[i];    }    System.out.println("总金额\t"+sum);}

}

package com.phone.week3.day1;

import java.util.Arrays;

public class Demo4 {

public static void main(String[] args) {    String[] words = { "c", "b", "a", "f", "d", "e" };    // 没排序的时候输出    for (int i = 0; i < words.length; i++) {        System.out.print(words[i] + "\t");    }    Arrays.sort(words); // 升序排    System.out.println();    // 升序输出    for (int i = 0; i < words.length; i++) {        System.out.print(words[i] + "\t");    }    System.out.println();    // 逆序输出    for (int i = words.length - 1; i >= 0; i--) {        System.out.print(words[i] + "\t");    }}

}

package com.phone.week3.day1;

import java.util.Arrays;

public class Demo10 {

public static void main(String[] args) {    int nums[]={3,2,5,8,7,6,1};    int num[] ={3,2,5,8,7,6,1};    for (int i : nums) {        System.out.print(i+"\t");    }    System.out.println();    //Arrays工具类里特有的方法来排序    Arrays.sort(nums);    Arrays.sort(num);    for (int i : nums) {        System.out.print(i+"\t");    }    System.out.println();    System.out.println(Arrays.equals(nums, num));    //把num数组里值全变成0    Arrays.fill(num, 0);    for (int i : num) {        System.out.print(i+"\t");    }    System.out.println();    int newArr[] = Arrays.copyOf(nums, 5);    for (int i : newArr) {        System.out.print(i+"\t");    }    System.out.println();    System.out.println(Arrays.toString(newArr));}//二分法查找private static void binarySearch(int[] nums) {    //查找7    boubbleSort(nums); //二分法查找一定是在排好序的基础上    int min = 0; //最小的下标    int max = nums.length-1; //最大下标    int mid = (min+max)/2; //找到中间下标    //如果你要找的数不是中间下标所对应的数，就继承找    while(nums[mid]!=5){        //如果中间下标所对应的值小于你要找的值        if(nums[mid]<5){            min = mid+1; //就改变最小下标的值        }        //如果中间下标所对应的值大于你要找的值        else if(nums[mid]>5){            max = mid-1; //就改变最大下标的值        }        mid = (min+max)/2; //继续找中间下标值    }    System.out.println();    System.out.println("5所在的下标位是:"+mid);}//插入排序法private static void insertSort(int[] nums) {    //插入排序    for (int i =1; i < nums.length; i++) {        for (int j = i; j >0; j--) {            if(nums[j-1]>nums[j]){                int temp = nums[j-1];                nums[j-1]=nums[j];                nums[j]=temp;            }        }    }    System.out.println();    for (int i : nums) {        System.out.print(i+"\t");    }}//选择排序private static void change(int[] nums) {    for (int i : nums) {        System.out.print(i+"\t");    }    System.out.println();    //选择排序    for (int i = 0; i < nums.length-1; i++) {        for (int j = i+1; j<nums.length; j++) {            if(nums[i]>nums[j]){                int temp = nums[i];                nums[i] = nums[j];                nums[j]=temp;            }        }    }    for (int i : nums) {        System.out.print(i+"\t");    }}/* * 冒泡排序 */private static void boubbleSort(int[] nums) {    for (int i : nums) {        System.out.print(i+"\t");    }    //输出的时候按照升序输出    //N个数字来排队，外层循环n-1,内层循环n-i-1    for (int i = 0; i < nums.length-1; i++) {        for (int j = 0; j < nums.length-i-1; j++) {            if(nums[j]>nums[j+1]){                int temp = nums[j];                nums[j]=nums[j+1];                nums[j+1]=temp;            }        }    }    //System.out.println();    for (int i : nums) {        System.out.print(i+"\t");    }}

}

package com.phone.week3.day1;

import java.util.Scanner;

/**
*
* @author Administrator
*
*/
public class Demo1 {

public static void main(String[] args) {    //声明数组的语法    //数据类型  数组名[] = new 数据类型 [6];    //声明数组的数据类型可以是任何数据类型，包括基本数据类型和引用数据类型,一旦分配好了指定类型的数组    //里面只能放同一种数据类型的数据    int score[] = new int[5]; //这里面只能放整型    String names[] = new String[35]; //这里面只能放字符串类型的数据    //声明数组时，这个中括号可以放在变量名的前面也可以放在变量名的后面    double []money = new double[12];    //给数组赋值有两种方式：    //1.静态赋值：声明数组和赋值一步完成    int sc[] = {1,2,4,6};//能过直接赋值的方式决定数组的长度    String nn[] = new String[]{"a","b","c","d"}; //还是根据赋值的方式来决定数组的长度，后面的中括号不能给数组的长度    //2.动态赋值:声明数组和赋值是分开完成的    //我们知道数组一旦分配了，在内存中就会连续的开辟一块空间，并且这些连接的空间都会被加上一个编号，编号从0开始，我们把这个编号称为下标    //我们就可以通过个这下标来给空间赋值或取值    score[1] = 90;    score[0] = 100;    //可以通过循环的方式动态赋值,从键盘接收5个分数，并存放在score这个数组里    Scanner in = new Scanner(System.in);    int sum = 0; //请总和的变量    for (int i = 0; i < 5; i++) {        System.out.println("请输入第"+(i+1)+"个分数:");        score[i] = in.nextInt(); //接收成绩        sum+=score[i]; //进行成绩累加    }    int avg = sum/5;//求平均分    System.out.println("5门课程的平均分是:"+avg);    //想查看这5门课程的成绩    for (int i = 0; i < 5; i++) {        System.out.println(score[i]);    }}

}

package com.phone.week3.day1;

public class Demo5 {

public static void main(String[] args) {    //装5名学生    Student[] stus = new Student[5]; //声明一个学生类型的数组长度为5    stus[0] = new Student("张三", 30, "深圳", "1509");    stus[1] = new Student("李四", 20, "湖南", "1509");    stus[2] = new Student("王五", 34, "湖北", "1509");    stus[3] = new Student("赵六", 28, "安徽", "1509");    stus[4] = new Student("田七", 26, "北京", "1509");    for (int i = 0; i < stus.length; i++) {        Student stu = stus[i];        System.out.println(stu.getName()+"\t"+stu.getAddress());    }}

}

package com.phone.week3.day1;

public class Demo8 {

public static void main(String[] args) {    for (int i = 0; i < args.length; i++) {        if(args[i]!=null&&!args[i].equals("")){            if(args[i].equals("add")){                System.out.println("增加用户");            }else if(args[i].equals("update")){                System.out.println("修改用户");            }else{                System.out.println("输入错误");            }        }    }}

}

package com.phone.week3.day1;

public class Demo7 {

public static void main(String[] args) {    String name[] = { "a", "b", "d", "e", "c" };    for (int i = 0; i < name.length; i++) {        System.out.print(name[i] + "\t");    }    System.out.println();    // 增强版的for循环    for (String s : name) {        System.out.print(s + "\t");    }    System.out.println();    // 装5名学生    Student[] stus = new Student[5]; // 声明一个学生类型的数组长度为5    stus[0] = new Student("张三", 30, "深圳", "1509");    stus[1] = new Student("李四", 20, "湖南", "1509");    stus[2] = new Student("王五", 34, "湖北", "1509");    stus[3] = new Student("赵六", 28, "安徽", "1509");    stus[4] = new Student("田七", 26, "北京", "1509");    for(Student s : stus){        System.out.print(s.getName()+"\t"+s.getAge());        System.out.println();    }    for (int i = 0; i < stus.length; i++) {        Student s = stus[i];        System.out.print(s.getName()+"\t"+s.getAge());        System.out.println();    }    int j[] = new int[]{1,2,3,4,5,6};    int ss[]={1,2,3};    test("rose",ss);}//可变参数public static void test(String name,int ... arg){    System.out.println(name);    for (int i = 0; i < arg.length; i++) {        System.out.println(arg[i]);    }}

}

package com.phone.week3.day1;

public class Student {

private String name;private int age;private String address;private String num;public String getName() {    return name;}public void setName(String name) {    this.name = name;}public int getAge() {    return age;}public void setAge(int age) {    this.age = age;}public String getAddress() {    return address;}public void setAddress(String address) {    this.address = address;}public String getNum() {    return num;}public void setNum(String num) {    this.num = num;}public Student(String name, int age, String address, String num) {    super();    this.name = name;    this.age = age;    this.address = address;    this.num = num;}@Overridepublic String toString() {    return "Student [name=" + name + ", age=" + age + ", address="            + address + ", num=" + num + "]";}

}