class PhysicsVector(name,x,y,z)
    method add(n,b)
	c := PhysicsVector(n, x + b.x, y + b.y, z + b.z)
	return c
    end
    method subtract(n,b)
	c := PhysicsVector(n, x - b.x, y - b.y, z - b.z)
	return c
    end
    method write_vector()
	write(name || " = " || x || "i + " || y || "j + " || z || "k")
    end
    method dot_vector(b)
	return x* b.x + y* b.y + z* b.z
    end
    method cross_vector(n,b)
	c := PhysicsVector(n, y * b.z - b.y * z, -(x * b.z - b.x * z), x * b.y - b.x * y)
	return c
    end
    method magnitude_vector()
	return sqrt(x*x + y*y + z*z)
    end
    method direction_vector_r()
	return atan(y,x)
    end
    method direction_vector_d()
	return atan(y,x) * 90.0 / asin(1.0)
    end
    method write_magnitude()
	write("magnitude of " || name || " = " || self.magnitude_vector())
    end
    method write_direction_r()
	write("direction of " || name || " in radians = " || self.direction_vector_r())
    end

    method write_direction_d()
	write("direction of " || name || " in degrees = " || self.direction_vector_d())
    end

    method write_dot(name, b )
	write("dot of " || self.name || " and " || b.name || " = " || self.dot_vector(b))
    end
    method write_cross(name, b )
	local ret
	write("cross of " || self.name || " and " || b.name || " = :")
	ret := self.cross_vector(name, b)
	ret.write_vector()
    end
end



procedure main()
    write("Unicon output")
    write("Chapter 2")
    write("Problem 5")

    a := PhysicsVector("a", 4.0, -3.0, 0.0)
    b := PhysicsVector("b", 6.0,  8.0, 0.0)
    
    c := a.add("c", b)
    d := b.subtract("d", a)
    e := a.subtract("e", b)
    
    f := PhysicsVector("f", 2.0, -3.0, 7.0)
    g := PhysicsVector("g", 12.0, 45.0, -8.0)
    h := PhysicsVector("h", -5.0, -3.0, 42.0)

    a.write_vector()
    b.write_vector()
    c.write_vector()
    d.write_vector()
    e.write_vector()
    
    a.write_magnitude()
    b.write_magnitude()
    c.write_magnitude()
    d.write_magnitude()
    e.write_magnitude()
    
    a.write_direction_r()
    b.write_direction_r()
    c.write_direction_r()
    d.write_direction_r()
    e.write_direction_r()
    
    a.write_direction_d()
    b.write_direction_d()
    c.write_direction_d()
    d.write_direction_d()
    e.write_direction_d()

    a.write_dot("a.a",a)
    a.write_dot("a.b",b)
    b.write_dot("b.a",a)
    a.write_dot("a.c",c)
    d.write_dot("d.a",a)
    a.write_dot("a.e",e)
    e.write_dot("e.a",a)

    a.write_cross("axa",a)
    a.write_cross("axb",b)
    b.write_cross("bxa",a)
    a.write_cross("axc",c)
    d.write_cross("dxa",a)
    a.write_cross("axe",e)
    e.write_cross("exa",a)

    f.write_cross("fxg",g)
    f.write_cross("fxh",h)
    g.write_cross("gxh",h)
    g.write_cross("gxf",f)
    h.write_cross("hxf",f)
    h.write_cross("hxg",g)

end