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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 value
const
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 value
const
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;
}
///:~
|
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
