include c:\cxpl\codes;  \intrinsic 'code' declarations

proc Euler(Step);       \Display cooling temperatures using Euler's method
int  Step;
int  Time;  real Temp;
[Text(0, "Step ");  IntOut(0, Step);  Text(0, " ");
Time:= 0;  Temp:= 100.0;
repeat  if rem(Time/10) = 0 then RlOut(0, Temp);
        Temp:= Temp + float(Step) * (-0.07*(Temp-20.0));
        Time:= Time + Step;
until   Time > 100;
CrLf(0);
];

real Time, Temp;
[Format(6,0);                   \display time heading
Text(0, "Time   ");
Time:= 0.0;
while Time <= 100.1 do          \(.1 avoids possible rounding error)
        [RlOut(0, Time);
        Time:= Time + 10.0;
        ];
CrLf(0);

Format(3,2);                    \display cooling temps using differential eqn.
Text(0, "Dif eq ");             \ dTemp(time)/dtime = -k*Temp
Time:= 0.0;
while Time <= 100.1 do
        [Temp:= 20.0 + (100.0-20.0) * Exp(-0.07*Time);
        RlOut(0, Temp);
        Time:= Time + 10.0;
        ];
CrLf(0);

Euler(2);                       \display cooling temps for various time steps
Euler(5);
Euler(10);
]