Help me with triangle.

Question

Help me to run this.


using System;

using System.Collections.Generic;

using System.Text;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args);

int Heron(int a, int b, int c)

{ 

    int p=(a+b+c)/2; 

    return sqrt(p*(p-a)*(p-b)*(p-c)); 

} 

    

 

int main()

{ 

    int a,b,c; 

    Console.WriteLine << " a: "; 

    Console.ReadLine >> a; 

    Console.WriteLine << " b: "; 

    Console.ReadLine >> b; 

    Console.WriteLine << " c: "; 

    Console.ReadLine >> c; 

    if(a<=0 || b<=0 || c<=0){ 

        Console.WriteLine << " All values must be great from 0!\n"; 

        system("pause"); 

        return 1; 

    } 

    if(!(c<a+b) || !(a<b+c) || !(b<a+c))

    { 

       Console.WriteLine << "Triangle no exist!\n"; 

       system("pause"); 

       return 1; 

    } 

    else

    { 

        Console.WriteLine << "area triangle = " << Heron(a,b,c) << endl; 

        system("pause"); 

        return 0; 

    } 

}