program debug1
c
c       John Mahaffy,  Penn State University, CmpSc 201 Example
c       1/26/96
c
c
c     Program to demonstrate debugging process
c
c     John Mahaffy, 1/23/96
c
      implicit none
      real mass1, mass2, vel1,vel2
      real avmass, ketot , avvel
      data mass1,mass2,vel1,vel2 /1.0,1.0,1.0,1.0/
c
c     mass1, and mass2 are the masses of two objects
c     vel1 and vel2 are there respective velocities
c     avmass and avvel are the mean values of mass and velocity respectively
c     ketot is the total kinetic energy of the two objects
c
c
c     calulate the mean value of system masses
c
      call meanval(2,mass1,mass2,vel1,vel2,avmass,avvel)
c
c     calculate the total kinetic energy
c
      ketot=    (mass1*vel1**2+mass2*vel2**2)/2.0
      print *, 'Mean mass is: ', avmass
      print *, 'Mean velocity is: ', avvel
      print *, 'Total Kinetic Energy is: ', ketot
      stop
      end
      subroutine meanval(rwf,x1,x2,y1,y2,xmean,ymean)
c
c     calculate a weighted mean for two pairs of numbers based
c     on a reciprocal weighting factor
c
c     John Mahaffy 6/07/95
c
      implicit none
      real rwf,x1,x2,y1,y2,xmean,ymean
c
c     rwf - reciprocal weighting factor converted to standard weighting factor
c     x1,x2 -  first pair of numbers
c     xmean -  weighted mean of first pair of numbers
c     y1,y2 -  second pair of numbers
c     ymean -  weighted mean of second pair of numbers
c
      rwf=1./rwf
      xmean=rwf*x1+(1.-rwf)*x2
      ymean=rwf*y1+(1.-rwf)*y2
      return
      end