triangles

program triangles;
uses wincrt;
var
xa,xb,xc,ya,yb,yc,ab,ac,bc:real;
isocele,equilateral,rectangle:boolean;
procedure coor(var x,y:real);
begin
writeln('entrer x');
readln(x);
writeln('entrer y');
readln(y);
end;
function dist(x1,y1,x2,y2:real):real;
begin
dist:=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
end;
function equi(a,b,c:real):boolean;
var
nat:boolean;
begin
nat:=false;
if (a=b) and  (a=c) then nat:=true;
equi:=nat;
end;
function iso(a,b,c:real):boolean;
var
nat:boolean;
begin
nat:=false;
if (((a=c) and (a<>b)) or ((a=b) and (a<>c)) or ((c=b) and (c<>a))) then nat:=true;
iso:=nat;
end;
function req(a,b,c:real):boolean;
var
nat:boolean;
begin
if ((a*a=b*b+c*c) or (b*b=a*a+c*c) or (c*c=a*a+b*b)) then nat:=true;
req:=nat;
end;
begin
writeln('entrer les coordonées de A');
coor(xa,ya);
writeln('entrer les coordonées de B');
coor(xb,yb);
writeln('entrer les coordonées de C');
coor(xc,yc);
AB:=dist(xa,ya,xb,yb);
BC:=dist(xb,yb,xc,yc);
Ac:=dist(xa,ya,xc,yc);

equilateral:=equi(AB,AC,BC);
isocele:=iso(AB,AC,BC);
rectangle:=req(AB,AC,BC);
if ((rectangle=false) and(isocele=false)and (equilateral=false)) then writeln ('ABC est un triangle quelconque');
if equilateral = true then writeln('le triangle est: équilateral');
if isocele=true then writeln('le triangle est: isocele');
if rectangle=true then writeln('le triangle est: rectangle');
writeln('Press <Enter> To Quit');
  readln();
end.