java判断三角形 java判断三角形并计算面积

抽象一个三角形类 Triangle

包括：
三个属性：三角形的三边 a, b, c（double 类型）
两个方法： 1. 判断三边是否能构成三角形，返回真假。 2. 计算三角形的面积（海伦公式）
编写主程序验证。
代码如下：

import java.lang.Math;

class Triangle {
    double a;
    double b;
    double c;

    void init(double a, double b, double c) {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    boolean isTriangle() {
        double temp = a > b ? a : b;
        temp = temp > c ? temp : c;
        if (a + b + c > 2 * temp) {
            return true;
        }
        return false;
    }

    double area() {
        double l = (a + b + c) / 2;
        l = l * (l - a) * (l - b) * (l - c);
        return Math.sqrt(l);

    }
}

public class Triangle_class {
    public static void main(String[] args) {
        Triangle t1 = new Triangle();
        Triangle t2 = new Triangle();
        t1.init(3, 4, 5);
        t2.init(3, 4, 7);
        System.out.println("Triangle1 is " + t1.isTriangle());
        if (t1.isTriangle()){
            System.out.println("Triangle1 is a triangle,and its area is " + t1.area());
        }
        else{
            System.out.println("Triangle2 isn't a triangle");
        }
        if (t2.isTriangle()){
            System.out.println("Triangle1 is a triangle,and its area is " + t2.area());
        }
        else{
            System.out.println("Triangle2 isn't a triangle");
        }
    }
}

Triangle1 is true
Triangle1 is a triangle,and its area is 6.0
Triangle2 isn't a triangle