C :

#include<stdio.h>
#include<string.h>
#include<math.h>
main()
{
	int i,j,k;
	int n,m;
	int sum=1;
	char a[10];
	scanf("%d",&n);	
	for(i=1;i<=n;i++)
	{
	    sum*=i; 	 
	}
	sprintf(a,"%d",sum);
	 k=strlen(a);
	 for(j=k-1;j>-1;j--)
	 if(a[j]=='0')
	 {
	
	 printf("%c",a[j-1]);
	  break;
}
	
} 

C++ :

#include<cstdio>
using namespace std;
int a[4]={1,3,9,7};
int b[4]={1,7,9,3};
int main()
{
	long long n,i,j,sum=1,count2=0,count3=0,count5=0,count7=0;
	scanf("%lld",&n);
	for(i=2;i<=n;i++)
	{
		int t=i;
		while(t%2==0)
		{
			count2++;
			t/=2;
		}
		while(t%3==0)
		{
			count3++;
			t/=3;
		}
		while(t%5==0)
		{
			count5++;
			t/=5;
		}
		while(t%7==0)
		{
			count7++;
			t/=7;
		}
		sum=sum*t;
		sum%=10;
	}
	if(count5>count2)
	{
		printf("5\n");
	}
	else
	{
		for(j=0;j<count2-count5;j++)
		{
			sum=sum*2;
			sum=sum%10;
		}
		sum=sum*a[count3%4];
		sum=sum%10;
		sum=sum*b[count7%4];
		sum%=10;
		printf("%lld\n",sum);
	}
	return 0;
} 

Pascal :

var
  i,j,n,w : longint;
  a : array[1..1000] of integer;

procedure fact(k : longint);
var
  x,i : longint;
begin
  x := 0;
  for i := 1 to w do
  begin
    a[i] := a[i]*k+x;
    x := a[i] div 10;
    a[i] := a[i] mod 10;
  end;
  while x>0 dO
  begin
    w := w+1;
    a[w] := x mod 10;
    x := x div 10;
  end;
end;

begin
  a[1] := 1;
  w := 1;
  readln(n);
  for i := 1 to n do fact(i);
  write(a[1]);
end.