Просмотр исходного текста страницы C++/Overload/Minus Minus

==Overload operator "++", "--"==



   
<source lang="cpp">
#include <iostream>
using namespace std;
class array {
  int nums[10];
public:
  array();
  void set(int n[10]);
  void show();
  array operator++();
  friend array operator--(array &ob);
};
array::array()
{
  int i;
  
  for(i = 0; i <10; i++) 
     nums[ i ] = 0;
}  
void array::set(int *n)
{
  int i;
  
  for(i = 0; i <10; i++) 
     nums[ i ] = n[ i ];
}
void array::show()
{
  int i;
  for(i = 0; i <10; i++) 
    cout << nums[ i ] << " ";
  cout << endl;
}
// Overload unary op using member function.
array array::operator++()
{
  int i;
  for(i = 0; i <10; i++) 
    nums[ i ]++;
  return *this;
}
// Use a friend.
array operator--(array &ob)
{
  int i;
  for(i = 0; i <10; i++) 
    ob.nums[ i ]--;
  return ob;
}
 
int main()
{
  array object1, object2, object3;
  int i[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  object1.set(i);
  object2.set(i);
  object3 = ++object1;
  object3.show();
  object3 = --object1;
  object3.show();
  return 0;
}
           
       </source>


==Overload the -- relative to MyClass class using a friend.==



   
<source lang="cpp">
#include <iostream>
using namespace std;
class MyClass {
  int x, y; 
public:
  MyClass() { 
     x=0; 
     y=0; 
  }
  MyClass(int i, int j) { 
     x=i; 
     y=j; 
  }
  void getXY(int &i, int &j) { 
     i=x; 
     j=y; 
  }
  friend MyClass operator--(MyClass &ob);              // prefix
  friend MyClass operator--(MyClass &ob, int notused); // postfix
};
// Overload -- (prefix) for MyClass class using a friend.
MyClass operator--(MyClass &ob)
{
  ob.x--;
  ob.y--;
  return ob;
}
// Overload -- (postfix) for MyClass class using a friend.
MyClass operator--(MyClass &ob, int notused)
{
  ob.x--;
  ob.y--;
  return ob;
}
int main()
{
  MyClass object1(10, 10);
  int x, y;
  --object1; // decrement object1 an object
  object1.getXY(x, y);
  cout << "(--object1) X: " << x << ", Y: " << y << endl;
  object1--; // decrement object1 an object
  object1.getXY(x, y);
  cout << "(object1--) X: " << x << ", Y: " << y << endl;
  return 0;
}

           
       </source>