program lights
     
C***********************************************************************
C  Given $150,000 how many traffic lights can be bought under the following
C	conditions:
C		1.  Each light is $5,000
C		2.  Istallation is $1,000
C		3.  Each light uses 420 kW-hrs per year
C		4.  $0.047 per kW-hr
C************************************************************************

      real lightcost, install, electusage, electcost
      real totcost, CostOfOne
      integer numlights
      
      lightcost = 5000.0
      install = 1000.0
      electusage = 420
      
      electcost = electusage * 0.047
      
 100  print *, 'How many lights do you think you can get for ',
     +         '$150,000?'
      read *, numlights
      
      totcost = 0.0
      CostOfOne = lightcost + install + electusage
      
      do 200 nlight = 1, numlights
          totcost = totcost + CostOfOne
C	  print *, nlight, totcost
 200  end do
 
      AmountLeft = 150000 - totcost
      
      if (AmountLeft .lt. 0) then
          print *, 'You overspent!  Try Again.'
	  goto 100
      else if (AmountLeft .gt. CostOfOne) then
          print *, 'You could still buy more!  You still have $',
     +             AmountLeft,' to spend. Try Again.'
	  goto 100
      else
          print *, 'You Guessed it! You can by ', numlights,
     +             ' stoplights for $150,000.'
      end if

      stop
      end