$AlexLat$

PROGRAM smith_04;USES crt; VAR i,n:integer; sum,k1,k2,k3,k4,p,dp,eps,Xn,Xk,X,dX:real; rSR,C,dC,r1,r2,r3,r4,cPR:array[1..3] of real;

 f1,f2:text;

 PROCEDURE Difur;

 BEGIN

 dC[1]:=C[3]*k2+C[2]*k4-C[1]*k1-C[1]*k3; {dcA}

 dC[2]:=C[1]*k3-C[2]*k4; {dcB}

 dC[3]:=C[1]*k1-C[3]*k2; {dcC}

 END;

 PROCEDURE RK_4;

 BEGIN

 Difur;

 FOR i:=1 TO n DO BEGIN

     r1[i]:=dC[i];

    C[i]:=cPR[i]+r1[i]*(dX/2);

 END;

 Difur;

 FOR i:=1 TO n DO BEGIN

    r2[i]:=dC[i];

     C[i]:=cPr[i]+r2[i]*(dX/2);

 END;

 Difur;

 FOR i:=1 TO n DO BEGIN

    r3[i]:=dC[i];

    C[i]:=cPR[I]+r3[i]*dX;

 END;

 Difur;

 FOR i:=1 TO n DO r4[i]:=dC[i];

 FOR i:=1 TO n DO rSR[i]:=((r1[i]+r2[i])*(r2[i]+r3[i])*(r3[i]+r4[i]))/6;

 END;

 PROCEDURE STROKA;

 BEGIN

WRITE(f2,'|',x:4:1,'|',c[1]:7:3,'|',c[2]:7:3,'|',c[3]:7:3,'|');

WRITE(f2,sum:3:0,'|',dc[1]:7:3,'|',dc[2]:7:3,'|',dc[3]:7:3,'|');

WRITELN(f2);

 END;

 PROCEDURE RUN;

 BEGIN

 WRITE('Step 3: Calculating data and writting results to file : out.rez');

 X:=Xn;

 dX:=0.05;

 REPEAT

   IF (ABS(x-p)<eps) THEN BEGIN

   Difur;

  sum:=C[1]+C[2]+C[3];

  STROKA;

  p:=p+dp;   END;

   FOR i:=1 TO n DO Cpr[i]:=C[i];

 RK_4;

  X:=X+dX;

 UNTIL(X>Xk);

 WRITELN(' - done.');

 END;

 PROCEDURE INIT;

 BEGIN

 ClrScr;

 WRITELN('Smith-04: v1.0 (c) 1998 by Mike Smith smith01@home.bar.ru ');

 WRITELN;

 WRITELN;

 WRITE('Step 1: Read data from file : in.dat');

 ASSIGN(f1,'in.dat');

 RESET(f1);

 READLN(f1,C[1],C[2],C[3]);

 READLN(f1,k1,k2,k3,k4);

 READLN(f1,Xn,Xk,dp,n,eps,p);

 WRITELN(' - done.');

 ASSIGN(f2,'out.rez');

 REWRITE(f2);

 WRITE('Step 2: Write header to file : out.rez');

 WRITELN(f2,'');

 WRITELN(f2,'| t,c| Ca,% | Cb,%| Cc,% | SUM | dCa | dCb | dCc |');

 WRITELN(f2,'=');

 WRITELN(' - done.');

 END;

 PROCEDURE DONE;

 BEGIN

 WRITELN('Step 4: Close all files and exiting...');

 CLOSE(f1);

 WRITELN(f2,'=');

 CLOSE(f2);

 WRITELN;

 END;

BEGIN

 INIT;

 RUN;

 DONE;

END.