#include <iostream>

using namespace std;

int gVar = 10;

class Foo
{
public:
  Foo ( void );
  explicit Foo ( int );
  ~Foo ( void );
private:
  int a;
};
Foo::Foo ( void )
{
  a = 0;
}
Foo::Foo ( int var )
{
  a = var;
}
Foo::~Foo ( void )
{
}

int main ( void )
{
  Foo thef ( gVar );  //遵循1
  
  return ( 0 );
}