Quite new to Swift : can't get my classes to interact - swift

Question

I have this code:
class Lion
{
var name:String = "Default"
var isAlive : Bool = false
func eat(cow:Cow)
{
cow.isAlive = false
print("Cow \(cow) was eaten by \(name)")
}
}
var lion1 = Lion()
lion1.name = "Mufasa"
lion1.isAlive = true
var lion2 = Lion()
lion1.name = "Simba"
lion1.isAlive = true
var lion3 = Lion()
lion1.name = "Scar"
lion1.isAlive = true
class Cow
{
var name:String = "Default"
var isAlive : Bool = false
func giveMilk ()
{
print("cow \(name) is now giving milk")
}
func die ()
{
print("Cow \(name) is now dead")
}
}
var cow1 = Cow()
cow1.name = "Moo1"
cow1.isAlive = true
var cow2 = Cow()
cow2.name = "Moo2"
cow2.isAlive = true
var cow3 = Cow()
cow3.name = "Moo3"
cow3.isAlive = true
var cow4 = Cow()
cow4.name = "Moo4"
cow4.isAlive = true
var cow5 = Cow()
cow5.name = "Moo5"
cow5.isAlive = true
var cow6 = Cow()
cow6.name = "Moo6"
cow6.isAlive = true
var cow7 = Cow()
cow7.name = "Moo7"
cow7.isAlive = true
var cow8 = Cow()
cow8.name = "Moo8"
cow8.isAlive = true
var cow9 = Cow()
cow9.name = "Moo9"
cow9.isAlive = true
var cow10 = Cow()
cow10.name = "Moo10"
cow10.isAlive = true
class Cat
{
var name:String = "Default"
func eatMouse (mouse : Mouse)
{
print("Mouse \(mouse) was eaten")
}
func getMilk (cow:Cow)
{
if cow.isAlive == true
{
cow.giveMilk()
}else{
print("A dead cow cannot provide milk")
}
}
}
var cat1 = Cat()
cat1.name = "Meow1"
var cat2 = Cat()
cat2.name = "Meow2"
class Mouse
{
var name:String = "Default"
func die ()
{
print("Mouse \(name) is dead")
}
}
var mouse1 = Mouse()
mouse1.name = "Micky"
var mouse2 = Mouse()
mouse2.name = "Mini"
var mouse3 = Mouse()
mouse3.name = "Rattata"
var mouse4 = Mouse()
mouse4.name = "Splinter"
When I run via Xcode , it tells me Cow, Mouse and Cat are "Use of undeclared type "class name" .
For the life of me, I can't figure it out ( Quite new so don't bash me).
After establishing the classes I am supposed to have the system run several different scenarios where mouse is dead, cat eats mouse, lion eats cow etc'.

Answer 1

This works. Try to move class definitions ahead of others.
class Mouse
{
var name:String = "Default"
func die ()
{
print("Mouse \(name) is dead")
}
}
class Cow
{
var name:String = "Default"
var isAlive : Bool = false
func giveMilk ()
{
print("cow \(name) is now giving milk")
}
func die ()
{
print("Cow \(name) is now dead")
}
}
class Lion
{
var name:String = "Default"
var isAlive : Bool = false
func eat(cow:Cow)
{
cow.isAlive = false
print("Cow \(cow) was eaten by \(name)")
}
}
var lion1 = Lion()
lion1.name = "Mufasa"
lion1.isAlive = true
var lion2 = Lion()
lion1.name = "Simba"
lion1.isAlive = true
var lion3 = Lion()
lion1.name = "Scar"
lion1.isAlive = true
var cow1 = Cow()
cow1.name = "Moo1"
cow1.isAlive = true
var cow2 = Cow()
cow2.name = "Moo2"
cow2.isAlive = true
var cow3 = Cow()
cow3.name = "Moo3"
cow3.isAlive = true
var cow4 = Cow()
cow4.name = "Moo4"
cow4.isAlive = true
var cow5 = Cow()
cow5.name = "Moo5"
cow5.isAlive = true
var cow6 = Cow()
cow6.name = "Moo6"
cow6.isAlive = true
var cow7 = Cow()
cow7.name = "Moo7"
cow7.isAlive = true
var cow8 = Cow()
cow8.name = "Moo8"
cow8.isAlive = true
var cow9 = Cow()
cow9.name = "Moo9"
cow9.isAlive = true
var cow10 = Cow()
cow10.name = "Moo10"
cow10.isAlive = true
class Cat
{
var name:String = "Default"
func eatMouse (mouse : Mouse)
{
print("Mouse \(mouse) was eaten")
}
func getMilk (cow:Cow)
{
if cow.isAlive == true
{
cow.giveMilk()
}else{
print("A dead cow cannot provide milk")
}
}
}
var cat1 = Cat()
cat1.name = "Meow1"
var cat2 = Cat()
cat2.name = "Meow2"
var mouse1 = Mouse()
mouse1.name = "Micky"
var mouse2 = Mouse()
mouse2.name = "Mini"
var mouse3 = Mouse()
mouse3.name = "Rattata"
var mouse4 = Mouse()
mouse4.name = "Splinter"