include "NSLog.incl"

double local fn Cooling( t as double, temp as double )
  return -0.07 * (temp - 20 )
end fn = 0.0

void local fn Euler( y as double, stepSize as int, endTime as double )
  int t = 0
  NSLog( @"\n  Step %2d: \b", stepSize )
  while ( t <= endTime )
    if ( t % 10 == 0 ) then NSLog( @" %7.3f \b", y )
    y += stepSize * fn Cooling( t, y )
    t += stepSize
  wend
end fn

void local fn Analytic
  NSLog( @"    Time: \b" )
  for int t1 = 0 to 100 step 10
    NSLog( @" %8d\b", t1 )
  next
  NSLog( @"\nAnalytic: \b" )
  for int t2 = 0 to 100 step 10
    NSLog( @"%9.3f\b", 20 + 80 * exp(-0.07 * t2 ) )
  next
end fn

fn Analytic
fn Euler( 100.0,  2.0, 100.0 )
fn Euler( 100.0,  5.0, 100.0 )
fn Euler( 100.0, 10.0, 100.0 )

HandleEvents