How can I write a program in Pascal that computes permutation of numbers using function subprogram for the factorial?

Answer 1

program MathCalculation (input,output);

{***********************************************************}

Function Factorial ( n : integer) : longint;

Begin

if (n=1) or (n=0) then

Factorial := 1

else

if (n=2) then

Factorial:=2

else Factorial := n * Factorial(n-1);

end;

{***********************************************************}

Var

N : integer;

{***********************************************************}

Begin

repeat

write(' Please input N :>');

readln(N);

until (N>=0);

writeln( Factorial(N));

End.