Program PopulationGrowth
!----------------------------------------------------------------------
!Tyler Martin			Engr225 Lab 2		25 January 2012
!				Population Growth Model
!----------------------------------------------------------------------

Implicit None
integer, parameter :: dp=selected_real_kind(15)
real(dp) :: InitialPop, Birth, Death, Time
integer :: FinalPop
character (10) :: period

write (*,*) "Hello, I will figure out the population at a given point in the future given current information."
write (*,*) "First of all, will this be in years, months, or days? Please enter year, month, or day."
read (*,*) period
write (*,*) "Please enter the current population." 
read (*,*) InitialPop
write (*,*) "Please enter the current birth rate."
read (*,*) Birth
write (*,*) "Please enter the current death rate."
read (*,*) Death
write (*,*) "Alright, now enter how many ", period, "(s) over which you'd like to calculate."
read (*,*) Time

Finalpop = InitialPop*exp((birth-death)*time)

write (*,*) "After ", time, period, "s there will be ", finalpop, "individuals."

stop
end program populationgrowth