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#include <iostream>using namespace std;
class Integer {
long i;
Integer* This() { return this; }
public:
Integer(long ll = 0) : i(ll) {}
// No side effects takes const& argument:
friend const Integer&
operator+(const Integer& a);
friend const Integer
operator-(const Integer& a);
friend const Integer
operator~(const Integer& a);
friend Integer*
operator&(Integer& a);
friend int
operator!(const Integer& a);
// Side effects have non-const& argument:
// Prefix:
friend const Integer&
operator++(Integer& a);
// Postfix:
friend const Integer
operator++(Integer& a, int);
// Prefix:
friend const Integer&
operator--(Integer& a);
// Postfix:
friend const Integer
operator--(Integer& a, int);
};// Global operators:const Integer& operator+(const Integer& a) {
cout << "+Integer\n";
return a; // Unary + has no effect
}const Integer operator-(const Integer& a) {
cout << "-Integer\n";
return Integer(-a.i);
}const Integer operator~(const Integer& a) {
cout << "~Integer\n";
return Integer(~a.i);
}Integer* operator&(Integer& a) { cout << "&Integer\n";
return a.This(); // &a is recursive!
}int operator!(const Integer& a) {
cout << "!Integer\n";
return !a.i;
}// Prefix; return incremented valueconst Integer& operator++(Integer& a) {
cout << "++Integer\n";
a.i++;
return a;
}// Postfix; return the value before increment:const Integer operator++(Integer& a, int) {
cout << "Integer++\n";
Integer before(a.i);
a.i++;
return before;
}// Prefix; return decremented valueconst Integer& operator--(Integer& a) {
cout << "--Integer\n";
a.i--;
return a;
}// Postfix; return the value before decrement:const Integer operator--(Integer& a, int) {
cout << "Integer--\n";
Integer before(a.i);
a.i--;
return before;
}int main() {
Integer a;
+a;
-a;
~a;
Integer* ip = &a;
!a;
++a;
a++;
--a;
a--;
return 0;
} ///:~
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本文转自FrankNie0101 51CTO博客，原文链接：http://blog.51cto.com/frankniefaquan/1934028，如需转载请自行联系原作者