java笔记

  1 import java.util.*;
  2 public class A
  3 {
  4     public static void main(String[] args)
  5     {
  6         System.out.println("-----------------------------------------");
  7         int a = 3/2;
  8         double b = (double)3/0;
  9         double c = (double)3.0/0;
 10         int d = -3/2;
 11         int e = -3/-2;
 12         int f = 3/-2;
 13         double g = 0/0.0;
 14         double h = -3/0.03;
 15         System.out.println("3/2 is: " + a);
 16         System.out.println("3/0 is: " + b);
 17         System.out.println("3.0/0 is: " + c);
 18         System.out.println("-3/2 is: " + d);
 19         System.out.println("-3/-2 is: " + e);
 20         System.out.println("3/-2 is: " + f);
 21         System.out.println("0/0.0 is: " + g);
 22         System.out.println("-3/0.03 is: " + h);
 23 
 24         
 25         System.out.println("-----------------------------------------");
 26         System.out.println("Use ternary operator:");
 27         int m1 = 1;
 28         int m2 = 2;
 29         int min = (m1 < m2) ? m1:m2;
 30         System.out.println("min is: " + min);
 31     
 32         System.out.println("-----------------------------------------");
 33         System.out.println("Please input a number:");
 34         Scanner sc = new Scanner(System.in);
 35         int s1 = sc.nextInt();
 36         if(s1 % 2 == 0) System.out.println(s1 + " is a even number.");
 37         else System.out.println(s1 + " is a uneven number.");
 38     
 39         
 40         System.out.println("-----------------------------------------");
 41         System.out.println("Please input your score:");
 42         Scanner sc2 = new Scanner(System.in);
 43         int s2 = sc2.nextInt();
 44         int temp = 0;
 45         if(s2 >= 90) temp = 1;
 46         if((s2 >= 80) && (s2 <= 90)) temp = 2;
 47         if((s2 >= 70) && (s2 <= 80)) temp = 3;
 48         if((s2 >= 60) && (s2 <= 70)) temp = 4;
 49         if(s2 < 60) temp = 5;
 50         switch (temp) {
 51             case 1:
 52                 System.out.println("You got A!");
 53                 break;
 54 
 55             case 2:
 56                 System.out.println("You got B!");
 57                 break;
 58 
 59             case 3:
 60                 System.out.println("You got C!");
 61                 break;
 62 
 63             case 4:
 64                 System.out.println("You got D!");
 65                 break;
 66 
 67             case 5:
 68                 System.out.println("You got E!");
 69                 break; 
 70         
 71             default:
 72                 break;
 73         }
 74 
 75         System.out.println("Please input your score:");
 76         Scanner sc3 = new Scanner(System.in);
 77         double score = sc3.nextInt();
 78         char level = score >= 90 ? ‘A‘ :
 79                     (score >= 80) && (score <= 90) ? ‘B‘ :
 80                     (score >= 70) && (score <= 80) ? ‘C‘ :
 81                     (score >= 60) && (score <= 70) ? ‘D‘ : ‘E‘;
 82         System.out.println("You got " + level + "!");
 83 
 84 
 85 
 86 
 87         System.out.println("-----------------------------------------");
 88         System.out.println("Common year and Leap year:");
 89         Scanner input = new Scanner(System.in);
 90         
 91         System.out.println("Please enter year:");
 92         int year = input.nextInt();
 93         if(year % 4 != 0 || year % 100 == 0 && year % 400 != 0) 
 94         {
 95             System.out.println(year + " is common year");
 96         }
 97         else 
 98         {
 99                 System.out.println(year + " is leap year");
100         }
101         
102     }
103 }