package test;
import java.util.Scanner;
public class Class {
    public static void main(String args[]){

    int a=0,b=0,c=0;
    Scanner Sc = new Scanner(System.in);
    System.out.println("请输入第三角形一条边");
    a=Integer.parseInt(Sc.next());
    System.out.println("请输入第三角形二条边");
    b=Integer.parseInt(Sc.next());
    System.out.println("请输入三角形第三条边");
    c=Integer.parseInt(Sc.next());
    if(a==b||b==c||a==c)
    System.out.println("等腰三角形");
    else if(a==b&&a==c)
    System.out.println("等边三角形");
    else if(a*a==b*b+c*c||b*b==c*c+a*a||b*b==a*a+c*c)
        System.out.println("直角三角形");
    else
        System.out.println("不是三角形");
        
        
    }
}
能运行但结果不对！！

if(a==b&&a==c)
 System.out.println("等边三角形");
else if(a==b||b==c||a==c)
 System.out.println("等腰三角形");

package com.fafu.study;

import java.util.Scanner;

public class TestTriangle {
    public static void main(String args[]) {
        Scanner Sc = new Scanner(System.in);
        System.out.print("请输入第三角形一条边 a = ");
        int a = Sc.nextInt();
        System.out.print("\n请输入第三角形二条边 b = ");
        int b = Sc.nextInt();
        System.out.print("\n请输入三角形第三条边c = ");
        int c = Sc.nextInt();

        if (a + b > c || a + c > b || b + c > a || a - b < c || a - c < b
                || b - c < a) { // 用于判断是否是三角形
            if (a == b || b == c || a == c)
                System.out.print("\n等腰三角形");
            else if (a == b && a == c)
                System.out.print("\n等边三角形");
            else if (a * a == b * b + c * c || b * b == c * c + a * a
                    || b * b == a * a + c * c)
                System.out.println("直角三角形");
            else
                System.out.print("\n不是三角形");

        }
    }
}

注：你没有对是否能够构成三角形进行判断

谢谢了！！