abstract class Funcion
{
	abstract public double f(double x);

	public double evaluar(double x)
	{
		return f(x);	
	}	
}

class FuncionExp extends Funcion
{
	public double f(double x)
	{
		return Math.exp(x);	
	} 
}

class FuncionLineal extends Funcion
{
	private double pendiente;
	private double xo,yo;
	
	public FuncionLineal(double pendiente,double xo,double yo)
	{
		this.pendiente = pendiente;
		this.xo = xo;
		this.yo = yo;	
	}
	
	public double f(double x)
	{
		return yo + pendiente*(x - xo);	
	}
	
} 

class prbFunciones
{
	public static void main(String arg[])
	{
		Funcion func = new FuncionExp();
	
		System.out.println(func.evaluar(0));
		System.out.println(func.evaluar(1));
	
		Funcion flineal = new FuncionLineal(0.5,0.0,1.0);
		System.out.println(flineal.evaluar(2.0));
		
		FuncionExp fe = new FuncionExp();
		
		System.out.println(fe.evaluar(2));
	}	
}