Whenever I try to use Xcode 11 to build C++ programs and type in the line: 

```
#include <iostream>

```

An error saying "'iostream' file not found shows up. The library I am using is libc++ and not libstdc++.

Other people dont seem to encounter this problem so I do not know what is going on. 

```
#include <iostream>
using namespace std;

int main()
{
    cout << "Hey, this really works!" << endl;
}

```