555+ : 25 ก.ย. 2552 program factorial;
uses crt;
var n : integer;
function fact(n : integer): integer;
var p,i : integer;
begin
p := 1;
for i := 1 to n do
p := p * i ;
fact := p;
end;
begin
clrscr;
writeln('Input Number');
readln(n);
writeln(n,'! = ',fact(n));
readln;

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