HeronsFormula.java

import java.io.*;
import java.util.Scanner;

public class HeronsFormula {

    /**
    *   Program:    HeronsFormula.java
    *   Purpose:    Yahoo! Answers triangle area question
    *   Creator:    Chris Clarke
    *   Created:    05.01.2014
    */

    public static void main(String[] args) {
        int n;  // number of triangles read from file
        int a, b, c;
        String area;

        try {
            // create scanner to read from file
            Scanner fileScan = new Scanner(new File("Triangles.txt"));
            /*
                Sample file (need to save as "Triangles.txt"):

                9
                7 8 9
                9 9 12
                6 5 21
                24 7 25
                13 12 5
                50 40 30
                10 10 10
                82 34 48
                4 5 6
            */

            // read lead value indicating the number of triangles to be evaluated
            n = fileScan.nextInt();
            System.out.println("A\tB\tC\tAREA");
            for (int i=0; i<n; i++) {
                a = fileScan.nextInt();
                b = fileScan.nextInt();
                c = fileScan.nextInt();

                System.out.printf("%d\t%d\t%d\t", a, b, c);
                calculateArea(a, b, c);
            } // end for
        } catch (FileNotFoundException e) {
            System.out.println("File not found!");
            return;
        } // end try/catch

    } // end main()

    public static void calculateArea(int a, int b, int c) {
        double s;
        double temp;
        double area = 0.0;

        s = (a + b + c) / 2.0;
        temp = s*(s-a)*(s-b)*(s-c);
        if (temp < 0) {
            System.out.println("This is not a triangle");
            return;
        } // end if
        area = Math.sqrt(temp);
        if (area==0) {
            System.out.println("This is not a triangle");
            return;
        } // end if
        System.out.printf("%2.4f%n", area);
    } // end calculateArea()
} // end class