using System;
using static System.Console;
using static System.Math;

public class main{

public static double erf(double z){
	Func<double,double> f = x => Exp(-x*x);
	double q = matlib.open4(f,0,z,acc:1e-4,eps:1e-4);
	return 2/Sqrt(PI)*q;
	}

public static void Main(){
	for(double z=-3; z<=3; z+=1.0/16)
		Console.WriteLine($"{z} {erf(z)}");

        WriteLine("\n");
        WriteLine("-2   -0.995322265");
        WriteLine("-1   -0.842700793");
        WriteLine("-0.5 -0.520499878");
        WriteLine("-0.2 -0.222702589");
        WriteLine(" 0.2  0.222702589");
        WriteLine(" 0.5  0.520499878");
        WriteLine(" 1    0.842700793");
        WriteLine(" 2    0.995322265");

	}


}//main