fig21_02.cpp

来自「经典vc教程的例子程序」· C++ 代码 · 共 39 行

// Fig. 21.2: fig21_02.cpp
// Demonstrating the static_cast operator.
#include <iostream.h>

class BaseClass {
public:
   void f( void ) const { cout << "BASE\n"; }
};

class DerivedClass: public BaseClass {
public:
   void f( void ) const { cout << "DERIVED\n"; }
};

void test( BaseClass * );

int main()
{
   // use static_cast for a conversion
   double d = 8.22;
   int x = static_cast< int >( d );
 
   cout << "d is " << d << "\nx is " << x << endl;

   BaseClass base;  // instantiate base object
   test( &base );   // call test

   return 0;
}
 
void test( BaseClass *basePtr )
{
   DerivedClass *derivedPtr;

   // cast base class pointer into derived class pointer    
   derivedPtr = static_cast< DerivedClass * >( basePtr );
   derivedPtr->f();   // invoke DerivedClass function f
}