fig22_01.cpp

来自「《c＋＋大学教程》源码」· C++ 代码 · 共 63 行

// Fig. 22.1: fig22_01.cpp
// Demonstrating operator const_cast. 
#include <iostream>

using std::cout;
using std::endl;
      
// class ConstCastTest definition
class ConstCastTest {
public:
   void setNumber( int );
   int getNumber() const;
   void printNumber() const;
private:
   int number;
};  // end class ConstCastTest

// set number
void ConstCastTest::setNumber( int num ) { number = num; }

// return number
int ConstCastTest::getNumber() const { return number; }

// output number
void ConstCastTest::printNumber() const
{
   cout << "\nNumber after modification: ";
	
   // cast away const-ness to allow modification
   const_cast< ConstCastTest * >( this )->number--;

   cout << number << endl;

}  // end printNumber

int main()
{
   ConstCastTest test;   // create ConstCastTest instance

   test.setNumber( 8 );  // set private data number to 8
   
   cout << "Initial value of number: " << test.getNumber();

   test.printNumber();
   return 0;

}  // end main

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