1 package TSort;
2 public class Client {
3     public static void main(String args[]) throws Exception{
4         new Menu();
5     }
6 }

 1 package TSort;
 2 import java.util.Scanner;
 3 public class Menu {
 4     private static Scanner in = new Scanner(System.in);
 5     public Menu() throws Exception
 6     {
 7         while(true){
 8             this.show();
 9         }
10     }
11     @SuppressWarnings("resource")
12     public void show() throws Exception{
13
14         System.out.println("======三角形种类=====");
15         System.out.println("[1] 进行三角形类型判断");
16         System.out.println("[e] 退出。");
17         while (in.hasNext()) {
18         String i = in.nextLine();
19         switch(i){
20             case "1":{
21                 int i_a,i_b,i_c;
22                 System.out.println("请输入三角形的三条边：");
23                 do {
24                     Scanner scana=new Scanner(System.in);
25                     String a=scana.next();
26                     Scanner scanb=new Scanner(System.in);
27                     String b=scanb.next();
28                     Scanner scanc=new Scanner(System.in);
29                     String c=scanc.next();
30                     if(IsInteger.IsNum(a)&&IsInteger.IsNum(b)&&IsInteger.IsNum(c))
31                     {
32                          i_a = Integer.parseInt(a);
33                          i_b = Integer.parseInt(b);
34                          i_c = Integer.parseInt(c);
35                          System.out.println(Sort.triangle(i_a, i_b, i_c));
36                          break;
37                     }
38                     else{
39                         System.out.println("输入不是整数！请重请输入三角形的三条边：");
40                     }
41                 } while (true);
42                 System.out.println("==========请继续选择===========");
43                 System.out.println("[1] 进行三角形类型判断");
44                 System.out.println("[e] 退出。");
45                 break ;
46         }
47             case "e":{
48                 System.exit(1) ;        // 系统退出
49                 break ;
50             }
51             default:{
52                 System.out.println("请选择正确的操作！") ;
53             }
54         }
55     }
56     }
57 }

 1 package TSort;
 2 public class IsInteger {
 3     public static boolean IsNum(String str)
 4      {
 5       if(str==null)
 6        {
 7          return false;
 8         }
 9       else{
10            try{
11             @SuppressWarnings("unused")
12             int num=Integer.valueOf(str);//把字符串强制转换为数字
13             return true;//是数字,返回true
14             }catch (Exception e) {
15              return false;
16             }
17         }
18     }
19 }

 1 package TSort;
 2 public class Sort{
 3     static String t1="边的值不在范围内";
 4     static String t2="不构成三角形";
 5     static String t3="等边三角形";
 6     static String t4="等腰三角形";
 7     static String t5="直角三角形";
 8     static String t6="一般三角形";
 9     public static String triangle(int a,int b,int c){
10         if(a<1 || a>100 ||b<1 || b>100|| c<1|| c>100)
11         {
12             return t1;
13         }
14         else if(a>=b+c ||b>=a+c||c>=a+b)
15         {
16             return t2;
17         }
18         else if(a==b &&b==c &&c==a){
19             return t3;
20         }
21         else if(a==b ||b==c ||c==a){
22             return t4;
23         }
24         else if(a*a+b*b==c*c ||b*b+c*c==a*a ||c*c+a*a==b*b){
25             return t5;
26         }
27         else {
28             return t6;
29         }
30     }
31 }