Data commit

Task/Euler-method/Pascal/euler-method.pas

@@ -0,0 +1,49 @@
+{$mode delphi}
+PROGRAM Euler;
+
+TYPE TNewtonCooling = FUNCTION (t: REAL) : REAL;
+
+CONST	T0	: REAL = 100.0;
+CONST	TR	: REAL = 20.0;
+CONST	k 	: REAL = 0.07;
+CONST	time    : INTEGER = 100; 	
+CONST	step    : INTEGER = 10;
+CONST	dt	: ARRAY[0..3] of REAL = (1.0,2.0,5.0,10.0);
+
+VAR	i	: INTEGER;
+
+FUNCTION NewtonCooling(t: REAL) : REAL;
+	BEGIN
+		NewtonCooling := -k * (t-TR);
+	END;
+	
+PROCEDURE Euler(F: TNewtonCooling; y, h : REAL; n: INTEGER);
+	VAR i: INTEGER = 0;
+	BEGIN
+		WRITE('dt=',trunc(h):2,':');
+		REPEAT
+			IF (i mod 10 = 0) THEN WRITE(' ',y:2:3);
+			INC(i,trunc(h));
+			y := y + h * F(y);	
+		UNTIL (i >= n);
+		WRITELN;
+	END;
+
+PROCEDURE Sigma;
+	VAR t: INTEGER = 0;
+	BEGIN
+		WRITE('Sigma:');
+		REPEAT
+			WRITE(' ',(20 + 80 * exp(-0.07 * t)):2:3);
+			INC(t,step);
+		UNTIL (t>=time);
+		WRITELN;
+	END;
+
+BEGIN
+	WRITELN('Newton cooling function: Analytic solution (Sigma) with 3 Euler approximations.');
+	WRITELN('Time: ',0:7,10:7,20:7,30:7,40:7,50:7,60:7,70:7,80:7,90:7);
+	Sigma;
+	FOR i := 1 to 3 DO
+		Euler(NewtonCooling,T0,dt[i],time);
+END.