Program Tam_Giac;
Uses crt;
Var a,b,c : Integer;
{ 1. Thu tuc nhap}
Procedure NhapABC (Var a, b, c : Integer);
Begin
Write( 'Nhap a:' ); Readln( a );
Write( 'Nhap b:' ); Readln( b );
Write( 'Nhap c:' ); Readln( c );
End;
{ 2. Ham tinh dien tich}
Function Dientich( a, b, c:Integer ) : Real;
Var dt,p : Real;
Begin
p := (a+b+c)/2;
dt := sqrt(p* (p-a)*(p-b)*(p-c));
Dientich := dt;
End;
{ 3. Thu tuc kiem tra va In kqua tinh dien tich (neu la tam giac) }
Procedure KiemTra_InDienTich ( a,b,c:Integer);
Begin
If ((a+b>c) and (b+c>a) and (a+c>b)) then
Writeln(' Ba canh tren tao thanh tam giac.dien tich', Dientich(a,b,c) )
Else
Writeln('Ba canh tren khongtao thanh tam giac');
End;
{ 3. Than chuong trinh chinh }
BEGIN
NhapABC(a,b,c);
KiemTra_InDienTich (a,b,c);
END.