Tính n! ( n<=100) với n được nhập từ bàn phím

uses crt;

var n,i:longint;s,s1:string;

{====================congsolon====================}
function add(a,b:string):string;
var i,x,y,du,s:longint;
    c:string;
begin
 while (length(a)<length(b)) do a:='0'+a;
 while (length(a)>length(b)) do b:='0'+b;
 du:=0;c:='';
 for i:=length(a) downto 1 do
  begin x:=ord(a[i])-48;
        y:=ord(b[i])-48;
        s:=x+y+du;
        du:=s div 10;
        c:=chr(s mod 10+48)+c;
  end;
 if (du>0) then c:='1'+c;
 add:=c;
end;

{====================nhansolon====================}
function nhan(a,b:string):string;
var n,i,j:longint;s,t:string;
begin
 n:=-1;s:='';
 for i:=length(a) downto 1 do
  begin n:=n+1;t:='';
        for j:=1 to ord(a[i])-48 do t:=add(t,b);
        for j:=1 to n do t:=t+'0';
        s:=add(t,s);
  end;
 nhan:=s;
end;
{====================chuongtrinh====================}
begin

readln(f,n);

s1:='1';

for i:=1 to n do 

  begin

    str(i,s);

    s1:=nhan(s1,i);

  end;

write(s1);

readln

end.

* Pascal:

uses crt;
var n:longint;
{---Ham-giai-thua---}
function gt(n:longint):longint;
var i:longint;
begin
   gt:=1;
   for i:=1 to n do gt:=gt*i;
   writeln(n,'!=',gt);
end;
{---Chuong-trinh-chinh---}
begin
   clrscr;
   repeat
      write('Nhap n (n<=100): '); readln(n);
   until n<=100;
   gt(n);
   readln
end.

* C++:

#include<bits/stdc++.h>
using namespace std;
//Ham giai thua
void giaithua(int n){
 int gt=1;
 for (int i=1;i<=n;i++)
  gt=gt*i;
 cout<<n<<"!="<<gt;
}
//Chuong trinh chinh
int main(){
 int n;
 cout<<"Nhap n (n<=100): "; cin>>n;
 giaithua(n);
}

* Python:

def gt(n):
    gt = 1
    
    for i in range(1,n+1):
        gt = gt * i
    return gt

n = int(input("Nhap n (n<=100): "))

print(n,"!=",gt(n))