hour12_3b.cpp

来自「《24学时精通c++》的随书源码的下半部分。欢迎下载学习。」· C++ 代码 · 共 68 行

 //Listing 12.3
 // Passing references to objects
 // was passreftoobj.cpp 
 #include <iostream>
 
 class SimpleCat
 {
 public:
     SimpleCat();
     SimpleCat(SimpleCat&);
     ~SimpleCat();
 
     int GetAge() const { return itsAge; }
     void SetAge(int age) { itsAge = age; }
 
 private:
     int itsAge;
 };
 
 SimpleCat::SimpleCat()
 {
     std::cout << "Simple Cat Constructor...\n";
     itsAge = 1;
 }
 
 SimpleCat::SimpleCat(SimpleCat&)
 {
     std::cout << "Simple Cat Copy Constructor...\n";
 }
 
 SimpleCat::~SimpleCat()
 {
     std::cout << "Simple Cat Destructor...\n";
 }
 
 const SimpleCat & FunctionTwo (const SimpleCat & theCat);
 
 int main()
 {
     std::cout << "Making a cat...\n";
     SimpleCat Frisky;
     std::cout << "Frisky is " << Frisky.GetAge() 
               << " years old\n";
 
     int age = 5;
     Frisky.SetAge(age);
     std::cout << "Frisky is " << Frisky.GetAge() 
               << " years old\n";
 
     std::cout << "Calling FunctionTwo...\n";
     std::cout << "address of Frisky " << &Frisky << "\n";
     FunctionTwo(Frisky);
     std::cout << "Frisky is " << Frisky.GetAge() 
               << " years old\n";
     return 0;
 }
 
 // functionTwo passes a ref to a const object
 const SimpleCat & FunctionTwo (const SimpleCat & theCat)
 {
     std::cout << "Function Two. Returning...\n";
     std::cout << "Frisky is now " << theCat.GetAge()
               << " years old \n";
     // theCat.SetAge(8);   const!
     std::cout << "address of Frisky in Function Two" << &theCat << "\n";
     return theCat;
 }