C++ :

#include<cstdio>
#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;
int check(char a[],char b[]);
int main()
{
    char str[21][101];
    char temp[100];
    int n,i,j;
      cin>>n;
    for(i=0;i<n;i++)
      cin>>str[i];
    for(i=0;i<n-1;i++)
      for(j=n-1;j>i;j--)
      {
        if(strcmp(str[j-1],str[j])<0)
        {
            strcpy(temp,str[j]);
            strcpy(str[j],str[j-1]);
            strcpy(str[j-1],temp);
        }
        if(strcmp(str[j-1],str[j])>0&&check(str[j-1],str[j]))
        {
            strcpy(temp,str[j]);
            strcpy(str[j],str[j-1]);
            strcpy(str[j-1],temp);
        }
      }
    for(i=0;i<n;i++)
      cout<<str[i];
    //system("pause");
    return 0;
}
int check(char a[],char b[])
{
    char s1[100],s2[100];
    strcpy(s1,a);
    strcpy(s2,b);
    strcat(s1,b);
    strcat(s2,a);
    if(strcmp(s1,s2)>0)
      return 0;
    else
      return 1;
}

Pascal :

var
 s:array[1..20] of string;
 t:string;i,j,k,n:longint;
begin
 readln(n);
 for i:=1 to n do begin
    read(k);
    str(k,s[i]);
 end;
 for i:=1 to n-1 do
    for j:=i+1 to n do
      if s[i]+s[j]<s[j]+s[i] then
      begin{交换}
        t:=s[i];
        s[i]:=s[j];
        s[j]:=t;
      end;
 for i:=1 to n do write(s[i]);
end.