uses crt;

const n=3;

var

   a    : array [1..n,1..n] of real;

   b,x  : array [1..n] of real;

   i,j,imax,lamda,sentinel,iter   : integer;

   es,ea,dummy,sum,old            : real;

begin

  clrscr;

  a[1,1]:= 4;a[1,2]:=-1;a[1,3]:=1;b[1]:=  7;

  a[2,1]:= 4;a[2,2]:=-8;a[2,3]:=1;b[2]:=-21;

  a[3,1]:=-2;a[3,2]:= 1;a[3,3]:=5;b[3]:= 15;

  x[1]:=1;x[2]:= 2;x[3]:=2;

  es:=0.00001;

  for i:=1 to n do

  begin

    dummy:=a[i,i];

    for j:=1 to n do

      a[i,j] := a[i,j]/dummy;

    b[i]:=b[i]/dummy;

  end;

  for i:=1 to n do

  begin

    sum:=b[i];

    for j:=1 to n do

      if i<>j then

        sum:=sum-a[i,j]*x[j];

    x[i]:=sum;

  end;

  lamda:=1;iter:=0;

  repeat

    inc(iter);

    sentinel:=1;

    for i:=1 to n do

     begin

      old:=x[i];

      sum:=b[i];

      for j:=1 to n do

        if i<>j then

          sum:=sum-a[i,j]*x[j];

      x[i]:=lamda*sum+(1-lamda)*old;

      if (sentinel=1) and (x[i]<>0) then

       begin

         ea:=abs((x[i]-old)/x[i]);

         if ea>es then

           sentinel:=0;

       end;

     end;

  until(sentinel=1);

  writeln('nilai x : ',x[1]:8:5);

  writeln('nilai y : ',x[2]:8:5);

  writeln('nilai z : ',x[3]:8:5);

  writeln('nilai ea      : ',es:8:5);

  writeln('nilai iterasi : ',iter);

  readln;