fig06_11.cpp

来自「经典vc教程的例子程序」· C++ 代码 · 共 30 行

// Fig. 6.11: fig06_11.cpp
// Demonstrating a public member function that
// returns a reference to a private data member.
// Time class has been trimmed for this example.
#include <iostream.h>
#include "time4.h"

int main()
{
   Time t;
   int &hourRef = t.badSetHour( 20 );

   cout << "Hour before modification: " << hourRef;
   hourRef = 30;  // modification with invalid value
   cout << "\nHour after modification: " << t.getHour();

   // Dangerous: Function call that returns
   // a reference can be used as an lvalue!
   t.badSetHour(12) = 74;
   cout << "\n\n*********************************\n"
        << "POOR PROGRAMMING PRACTICE!!!!!!!!\n"
        << "badSetHour as an lvalue, Hour: "
        << t.getHour()
        << "\n*********************************" << endl;

   return 0;
}