Category : Pascal Source Code
Archive   : PAS-SCI.ZIP
Filename : DETERM.PAS

program determ; { -> 55 }
{ pascal program to calculate the determinant of a 3-by-3matrix }

type ary2 = array[1..3,1..3] of real;

var a : ary2;
n : integer;
yesno : char;
d : real;

procedure get_data(var a: ary2;
var n: integer);

{ get values for n and arrays x,y }

var i,j : integer;

begin
n:=3;
writeln;
for i:=1 to n do
begin
for j:=1 to n do
begin
write(j:3,':');
readln(a[i,j])
end { j-loop }
end; { i-loop }
writeln;
for i:=1 to n do
begin
for j:=1 to n do
write(a[i,j]:7:4,' ');
writeln
end;
writeln
end; { procedure get_data }




function deter(a: ary2): real;
{ calculate the determinant of a 3-by-3matrix }

var
sum : real;

begin
sum:=a[1,1]*(a[2,2]*a[3,3]-a[3,2]*a[2,3])
-a[1,2]*(a[2,1]*a[3,3]-a[3,1]*a[2,3])
+a[1,3]*(a[2,1]*a[3,2]-a[3,1]*a[2,2]);
deter:=sum
end;



begin { MAIN program }
ClrScr;
repeat
get_data(a,n);
d:=deter(a);
writeln('The determinant is',d);
writeln;
write('More?');
readln(yesno);
ClrScr
until (yesno<>'Y')and(yesno<>'y')
end.