19
Did you:
#include <sstream>
Also, the second to last line should be endl (nb: lower-case L) not end1 (number one).
The code below compiles and works correctly with G++ 4.2.1 on MacOS X
#include <iostream>
#include <sstream>
int main() {
std::stringstream out;
out << "foo" << std::endl;
std::string c = out.str();
std::cout << c;
}
Omitting the #include <sstream> causes exactly the same error on my system as your first error.