Area of Triangle, Java

问题

I'm trying to build an app which computes the area of a triangle, as per my homework assignment. Not quite sure where I'm going wrong, but I input the lengths of the triangle and would like the proper area displayed according to Heron's formula: sqrt (s(s-a) (s-b) (s-c)). All I'm getting for output is -0.0. Here is the code:

import java.lang.Math;
public class Formula
{
    double area; double s;
    public double findArea(double sideA, double sideB, double sideC)
    { 
        s = 1/2 * (sideA + sideB + sideC);
        area = Math.sqrt(s*(s-sideA)*(s-sideB)*(s-sideC));
        System.out.println("The area of the triangle is " + area);
        return area;
    }
}

And then I have another file for the main args

import java.util.Scanner;

public class findTriangleArea {

    /**
     * @param args
     */

    public static void main(String[] args) {

        // TODO Auto-generated method stub
        Formula triangle = new Formula();
        double a,b,c;

        // input triangle lengths a, b, c 
        Scanner inputTriangle = new Scanner(System.in);
        System.out.println("Please enter triangle side a");
        a = inputTriangle.nextDouble();
        System.out.println("Please enter triangle side b");
        b = inputTriangle.nextDouble();
        System.out.println("Please enter triangle side c");
        c = inputTriangle.nextDouble();
        triangle.findArea(a, b, c);
    }
}

回答1:

1/2 is being computed in integer arithmetic, so like with all integer division, it's truncated -- in this case, to 0. Just write 0.5 and you'll be fine.

来源：https://stackoverflow.com/questions/10290316/area-of-triangle-java