Question

I’ve written a simple c++ program, test.cpp:

#include <iostream>
#include <string>

using namespace std;

int main() {
  string s;
  cin >> s;
  cout << s << endl;
  return 0;
}

Why does runnning gcc test.cpp -o mytest give me these errors, and more?

Undefined symbols for architecture x86_64:
  "std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string()", referenced from:
      _main in cc8rGYVq.o
  "std::cin", referenced from:
      _main in cc8rGYVq.o

Answer 1

Don’t use the executable named gcc to compile and link C++ programs; you must use g++. Not only does it select the appropriate compiler options, it also links with the right libraries for your language (which is the problem you’re having here.)