Task: Heronian triangles
C#: using System;
using System.Collections.Generic;

namespace heron
{
    class Program{
        static void Main(string[] args){           
            List<int[]> list = new List<int[]>();
            for (int c = 1; c <= 200; c++)
                for (int b = 1; b <= c; b++)
                    for (int a = 1; a <= b; a++)
                        if (gcd(a, gcd(b, c)) == 1 && isHeron(heronArea(a, b, c)))
                            list.Add(new int[] { a, b, c, a + b + c, (int)heronArea(a, b, c)});
            sort(list);
            Console.WriteLine("Number of primitive Heronian triangles with sides up to 200: " + list.Count + "\n\nFirst ten when ordered by increasing area, then perimeter,then maximum sides:\nSides\t\t\tPerimeter\tArea");
            for(int i = 0; i < 10; i++)
                Console.WriteLine(list[i][0] + "\t" + list[i][1] + "\t" + list[i][2] + "\t" + list[i][3] + "\t\t" + list[i][4]);
            Console.WriteLine("\nPerimeter = 210\nSides\t\t\tPerimeter\tArea");
            foreach (int[] i in list)
                if (i[4] == 210)
                    Console.WriteLine(i[0] + "\t" + i[1] + "\t" + i[2] + "\t" + i[3] + "\t\t" + i[4]);     
        }
        static bool isHeron(double heronArea){
            return heronArea % 1 == 0 && heronArea != 0;
        }
        static double heronArea(int a, int b, int c){
            double s = (a + b + c) / 2d;
            return Math.Sqrt(s * (s - a) * (s - b) * (s - c));
        }
        static int gcd(int a, int b){
            int remainder = 1, dividend, divisor;
            dividend = a > b ? a : b;
            divisor = a > b ? b : a;
            while (remainder != 0){
                remainder = dividend % divisor;
                if (remainder != 0){
                    dividend = divisor;
                    divisor = remainder;
                }
            }
            return divisor;
        }
        static void sort(List<int[]> list){
            int[] temp = new int[5];
            bool changed = true;
            while(changed){
                changed = false;
                for (int i = 1; i < list.Count; i++)
                    if (list[i][4] < list[i - 1][4] || list[i][4] == list[i - 1][4] && list[i][3] < list[i - 1][3]){
                        temp = list[i];
                        list[i] = list[i - 1];
                        list[i - 1] = temp;
                        changed = true;
                    }                
            }
        }
    }
}

VB: Function heroArea(a As Integer, b As Integer, c As Integer) As Double
    s = (a + b + c) / 2
    On Error GoTo Err
    heroArea = Sqr(s * (s - a) * (s - b) * (s - c))
    Exit Function
Err:
    heroArea = -1
End Function
 
Function hero(h As Double) As Boolean
    hero = (h - Int(h) = 0) And h > 0
End Function
 
Public Sub main()
    Dim list() As Variant, items As Integer
    Dim a As Integer, b As Integer, c As Integer
    Dim hArea As Double
    Dim tries As Long
    For a = 1 To 200
        For b = 1 To a
            For c = 1 To b
                tries = tries + 1
                If gcd(gcd(a, b), c) = 1 Then
                    hArea = heroArea(a, b, c)
                    If hero(hArea) Then
                        ReDim Preserve list(items)
                        list(items) = Array(CStr(hArea), CStr(a + b + c), CStr(a), CStr(b), CStr(c))
                        items = items + 1
                    End If
                End If
            Next c
        Next b
    Next a
    list = sort(list)
    Debug.Print "Primitive Heronian triangles with sides up to 200:"; UBound(list) + 1; "(of"; tries; "tested)"
    Debug.Print
    Debug.Print "First 10 ordered by area/perimeter/sides:"
    Debug.Print "area       perimeter        sides"
    For i = 0 To 9
        Debug.Print Format(list(i)(0), "@@@"), Format(list(i)(1), "@@@"),
        Debug.Print list(i)(2); "x"; list(i)(3); "x"; list(i)(4)
    Next i
    Debug.Print
    Debug.Print "area = 210:"
    Debug.Print "area       perimeter        sides"
    For i = 0 To UBound(list)
        If Val(list(i)(0)) = 210 Then
            Debug.Print Format(list(i)(0), "@@@"), Format(list(i)(1), "@@@"),
            Debug.Print list(i)(2); "x"; list(i)(3); "x"; list(i)(4)
        End If
    Next i
End Sub