fprint:=proc(ncase,neqn,t,u)
#
# Procedure fprint displays the numerical and
# exact solutions to the 2 x 2 ODE problem
#
# Type variables
  global a, b:
  local e1, e2, ue, diff, i:
#
# Define arrays
  ue:=array(1..neqn): diff:=array(1..neqn):
#
# Print a heading for the solution at t = 0 
  if (t <= 0.0) then
#
#   Label for ODE integrator
#
#   Fixed step modified Euler 
    if (ncase = 1) then
      printf(`\n\n euler2a integrator\n\n`);
# 
#   Variable step modified Euler
    elif (ncase = 2) then
      printf(`\n\n euler2b integrator\n\n`);
#
#   Fixed step classical fourth order RK
    elif (ncase = 3) then
      printf(`\n\n rkc4a integrator\n\n`);
#
#   Variable step classical fourth order RK 
    elif (ncase = 4) then
      printf(`\n\n rkc4b integrator\n\n`);
#
#   Fixed step RK Fehlberg 45 
    elif (ncase = 5) then    
      printf(`\n\n rkc45a integrator\n\n`);
#        
#   Variable step RK Fehlberg 45 
    elif (ncase = 6) then
      printf(`\n\n rkc45b integrator\n\n`);
    end if:
#
# Heading
  printf(`         t         u1         u2     u1-ue1     u2-ue2\n`);
#
# End of t = 0 heading
  end if:
#
# Numerical and analytical solution output 
#
#   Exact solution eigenvalues
    e1:=-(a-b):
    e2:=-(a+b):
#
#   Analytical solution
    ue[1]:=exp(e1*t)-exp(e2*t):
    ue[2]:=exp(e1*t)+exp(e2*t):
#
#   Difference between exact and numerical solutions
    for i from 1 to neqn do
      diff[i]:=u[i]-ue[i]:
    end do:
#
#   Display the numerical and exact solutions, and their difference
    printf(`%10.2f %10.5f %10.5f %10.5f %10.5f \n`,t,u[1],u[2],diff[1],diff[2]);
#
# End of fprint
  end: