C :

#include<stdio.h>
void main()
{
	int a[1001]={0},i,n,t,r=0,s=0;
	scanf("%d",&n);
	for (i=0;i<n;i++)
	{
		scanf("%d",&t);
		if (!a[t]) s++;
		a[t]=1;
	}
	printf("%d\n",s);
	for (i=0;i<1001;i++)
 	if (a[i]) 
	{
		printf("%d",i);
		r++;
		if (r!=s) printf(" ");
	}
}

C++ :

#include <iostream>
#include<algorithm>
using namespace std;
int main()
{
	int n;
	cin >> n;
	int a[100];
	int b;
	int j;
	for (j = 0; n--;){
		cin >> b;
		int i;
		for (i = 0; i < j; i++){
			if (b == a[i])
				break;
		}
			if (i == j){
				a[j] = b;
				j++;
		}
	}
	sort(a, a + j);
	cout << j << endl;
	for (int i = 0; i < j;i++)
	if (i)
		cout << " " << a[i];
	else
		cout << a[i];
}

Pascal :

var n,i,x,j:longint;a,b:array[1..1000]of longint;
begin
 readln(n);
 for i:=1 to n do
  begin
   read(x);
   a[x]:=1
  end;
 for i:=1 to 1000 do if a[i]=1 then begin inc(j);b[j]:=i;end;
 writeln(j);
 for i:=1 to j-1 do write(b[i],' ');write(b[j])
end.

Java :

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Scanner;
import java.util.TreeSet;

public class Main {
	public static void main(String[] args) {
		TreeSet<Integer> set  = new  TreeSet<>();
		Scanner s = new Scanner(System.in);
		int n = s.nextInt();
		while(n>0){
			int r = s.nextInt();
			set.add(r);
			n--;
		}
		Integer num =null;
		System.out.println(set.size());
		while((num = set.pollFirst())!=null){
			System.out.print(num+" ");
		}
	}
}