Const
     maxn = 10;
Type
    Data = Real;
    Matrix = Array[1..maxn, 1..maxn] of Data;
    Vector = Array[1..maxn] of Data;
Procedure ReadSystem(n: Integer; var a: Matrix; var b: Vector);
Var
   i, j, r: Integer;
Begin
     for j:=1 to n do begin
         for i:=1 to n do read(a[i,j]);
         read(b[j])
     end;
End;
Procedure WriteX(n :Integer; x: Vector);
Var
   i: Integer;
Begin
     For i := 1 to n do
         Writeln('x', i, ' = ', x[i]);
End;
Function Seidel(n: Integer; a: Matrix; b: Vector; var x: Vector; e: Data)
:Boolean;
Var
   i, j: Integer;
   s1, s2, s, v, m: Data;
Begin
     For i := 1 to n do begin
         s := 0;
         For j := 1 to n do
             If j <> i then
                s := s + Abs(a[i, j]);
         If s >= Abs(a[i, i]) then begin
            Seidel := false;
            Exit;
         end;
     end;
     Repeat
         m := 0;
         For i := 1 to n do begin
             s1 := 0;
             s2 := 0;
             For j := 1 to i - 1 do
                 s1 := s1 + a[i, j] * x[j];
             For j := i to n do
                 s2 := s2 + a[i, j] * x[j];
             v := x[i];
             x[i] := x[i] - (1 / a[i, i]) * (s1 + s2 - b[i]);
             If Abs(v - x[i]) > m then
                m := Abs(v - x[i]);
         end;
     Until m < e;
     Seidel := true;
End;
Var
    n, i: Integer;
    a: Matrix;
    b, x: Vector;
    e: Data;
Begin
      Writeln('Linear Equations Solution using Seidel Method...');
      Writeln('Enter the number of equations:');
      Repeat
        Read(n);
      Until (n > 0) and (n <= maxn);
      Writeln('Enter the approximation level E:');
      Repeat
        Read(e);
      Until (e > 0) and (e < 1);
      Writeln('Enter the extended matrix A:');
      ReadSystem(n, a, b);
      Writeln;
      For i := 1 to n do
          x[i] := 0;
      If Seidel(n, a, b, x, e) then begin
         Writeln('Calculations resulted in...');
         WriteX(n, x);
      end
      else
          Writeln('Seidel`s method is not applicable to this system...');
      Writeln;
      read(n)
End.