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  • JAVA流程控制

    JAVA流程控制

    example1:

    --输出九九乘法表

    public class chengfabiao {

    public static void main (String[] args){

                                             int i = 1;

                                             int j = 1;

                                             for(i<=9;i++){

                                                   for(j<=9;j++){

                                                        if(i>j){

                                                                  system.out.print('        ');--打印8个空格使得输出内容格式形成一个上三角;

                                                                    }

                                                         else{

                                                                  syetem.out.printf('%d*%d=%2d',i,j,i*j);

                                                                  }}

                                                     system.out.printf(' ');        

    }}

    example2:

    --判断月份天数

    import java.util.*;                                                                                         -------代表导入util包下的所有类

    public class panduan{

               public static void main(String[] args){

                                      int days = 0;

                                     Scanner.sc =new Scanner(System.in);                    -------Scanner 是util包下的一个类,sc是一个实例或者说是对象!new 是一个创建对象的方法…… Scanner这个类最实用的地方表现在获取控制台输入

                                     System.out.println('输入年份:');

                                     int year = sc .nextInt();                                           ---------获取键盘的输入: 如果执行到了这一行,那么程序会暂停,等待你在控制台输入,然后把输入的整数值赋给整形变量 year

                                     System.out.println('输入月份:');   

                                    int month = sc .nextInt();

                                    switch(month){

                                                             case 1:

                                                             case 3:

                                                             case 5:

                                                             case 7:

                                                             case 8:

                                                             case 10:

                                                             case 12:

                                                                          System.out.println('本月有31天');   

                                                                          break;

                                                             case 4:

                                                             case 6:

                                                             case 9:

                                                             case 11:

                                                                          System.out.println('本月有30天');   

                                                                          break;

                                                             case 2:

                                                                        if(year%4==0  && year%100!=0  || year%400==0)

                                                                        {System.out.println('本月有29天');  }

                                                                         else

                                                                         {System.out.println('本月有28天');  }

                                                                          break;

                                                           default:

                                                                        System.out.println('月份输入错误');  

                                                                         System.exit(0);                                                        ---------  强制结束程序

                                                           } } }

    备注:

    switch (表达式){  case 值1 : 语句1 break;  case 值2 : 语句2 break;  ...  default : 语句n break;  }       

    Java.util包中包含的类:

    Java.util.ArrayDeque类
    Java.util.ArrayList类
    Java.util.Arrays类
    Java.util.BitSet类
    Java.util.Calendar类
    Java.util.Collections类
    Java.util.Currency类
    java.util.Date类
    java.util.Dictionary类
    java.util.EnumMap类
    java.util.EnumSet类
    java.util.Formatter类
    java.util.GregorianCalendar类
    java.util.HashMap类
    java.util.HashSet类
    java.util.Hashtable类
    java.util.IdentityHashMap类
    java.util.LinkedHashMap类
    java.util.LinkedHashSet类
    java.util.LinkedList类
    java.util.ListResourceBundle类
    java.util.Locale类
    java.util.Observable类
    java.util.PriorityQueue类
    java.util.Properties类
    java.util.PropertyPermission类
    java.util.PropertyResourceBundle类
    java.util.Random类
    java.util.ResourceBundle类
    java.util.ResourceBundle.Control类
    java.util.Scanner类
    java.util.ServiceLoader类
    java.util.SimpleTimeZone类
    java.util.Stack类
    java.util.StringTokenizer类
    java.util.Timer类
    java.util.TimerTask类
    java.util.TimeZone类
    java.util.TreeMap类
    java.util.TreeSet类
    java.util.UUID类
    java.util.WeakHashMap类
    java.util.Interfaces接口
    java.util.Exceptions接口
    java.util.Formatter.BigDecimalLayoutForm接口  
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  • 原文地址:https://www.cnblogs.com/shanshanliu/p/6236304.html
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