Решение СЛАУ методом Гаусса

program Gauss;
Uses Crt;
Var n,i,j,k,r:integer;
max,c,s,M:real;
a:array [1..100,1..100] of real;
b:array [1..100] of real;
x:array [1..100] of real;
begin
ClrScr;
Write('Vvedite razmernost:');
Readln(n);
for i:=1 to n do
begin
for j:=1 to n do
begin
Write('a[',i,',',j,']=');
Read(a[i,j]);
end;
Write('b[',i,']=');
Readln(b[i]);
Writeln;
end;
for k:=1 to n do
begin
max:=abs(a[k,k]);
r:=k;
for i:=k+1 to n do
if abs(a[i,k])>max then
begin
max:=abs(a[i,k]);
r:=i;
end;
for j:=1 to n do
begin
c:=a[k,j];
a[k,j]:=a[r,j];
a[r,j]:=c;
end;
c:=b[k];
b[k]:=b[r];
b[r]:=c;
for i:=k+1 to n do
begin
M:=a[i,k]/a[k,k];
for j:=k to n do
begin
a[i,j]:=a[i,j]-a[k,j]*M;
end;
b[i]:=b[i]-b[k]*M;
end;
end;
Writeln('Stupenchatij vid sistemi:');
Writeln;
for i:=1 to n do
begin
for j:=1 to n do
Write(a[i,j]:5:1,' ');
Write('|');
Writeln(b[i]:5:1);
Writeln;
end;
Writeln('Otvet:');
Writeln;
if a[n,n]=0 then
if b[n]=0 then
Writeln('Uravnenie imeet beskonechnoe mnogestvo resheniy')
else
Writeln('Uravnenie ne imeet resheniy')
else
begin
for i:=n downto 1 do
begin
s:=0;
for j:=i+1 to n do
begin
s:=s+a[i,j]*x[j];
end;
x[i]:=(b[i]-s)/a[i,i];
end;
for i:=1 to n do
Writeln('x[',i,']=',x[i]:5:1);
end;
readln;
end.