#include <iostream>
#include <string>
using std::string;

string s;                 // DEFINES s to be the empty string.
string s = "AP";          // Double definition: ERROR

int f(int i){             // DEFINES f to a particular function from
  return i + 1;           // int to int
}

int f(int j){             // DEFINES f again - double definition - ERROR
  return j - 1;           
}

double f(double j){       // DEFINES f on double - overload - OK
  return j - 1;           
}

int g(int);               // DECLARES g. OK

struct Date;              // DECLARES struct Date. OK

int f()                   // DEFINES the parameterless function f - an overload
{
  Date d;                 // Incomplete type. The details of of type Date must be known here. ERROR
  f(1);                   // OK
  g(2);                   // OK
}