calculate all possibileties

[ISLAMmedia]

my probleme is I want it to calculate all possibileties for example
the String "AB"
I want the input to be like this :
AA
AB
BA
BB
etc..

  #include <iostream>
#include <string>
using namespace std;
int main ()
	{
     string txt="AB" ;
	 string container ="";
	 int i =0 ;
	 fu:
	if (container.length()==2)
	{
		cout << container<<endl;
		if (container.length()==2)
	{
		goto fu;
		
	}
	}
	else
	{
		for ( i  ;i<2;i++)
		{
			string old = txt;
			    
				container += txt.at(i);
				goto fu;
				old = txt;
		}
	}

		
	 system("pause");

   }