help a newbie :(

I'm just starting C++, and I need help with a something....
How can I concatenate numerical data (integers/longs) to string values??
I've tried some things but nothing works..

Thanks in advance for any help..

Code:

char * l_strcat( char str[], long my_long) {
  char temp[MAX];
  sprintf(temp, " %Li ", my_long);
  return strcat(str, temp);
 }

I'll try then:

Code:

template<typename T>
void mystrcat(std::string& str, T t)
{
  std::stringstream sout;
  sout << str << t;
  str = sout.str();
}

int main()
{
  using namespace std;
  string p = "Sang-drax";
  mystrcat(p,123);
  cout << p;
}