C + + operator overloading

Source: Internet
Author: User
Tags bitwise

1#include <iostream>2#include <string.h>3 using namespacestd;4 5 //pretending to write an output class6 classOutput7 {8  Public:9     //operator overload mode oneTenoutput&operator>> (stringb) One     { Acout <<b; -         return* This; -     } the  -     //operator overloading mode two -Friend output&operator>> (output& out,inti) -     { +cout <<"output a integer:"<<i; -         return  out; +     } A  atOutputoperator! (void) -     { -cout <<"hehe!\n"; -         return* This; -     } - }; in  - intMain () to { +Output out; -     stringHello ="Hello, world!\n."; the      out>>Hello; *      out>>"Hello, world!\n."; $      out>>"Hello, world!\n.">>"Good bye!\n";Panax Notoginseng      out= ! out; -  the      out>>23333>>"\ n"; +  Acout <<"Hello World"<<Endl; the     return 0; +}

Directly look at the code, C + + operator overloading has two implementations, one is overloaded into a member of the class function, the other is the overload as a friend function, the member function has the this pointer, so one less parameter.

Attach operator Precedence

Priority Level operator Description Example Binding Nature
1 ()
[]
-
.
::
++
--
The parentheses operator that adjusts the precedence
Array Subscript access operator
To access a member's operator by pointing to the object's pointer
Operator that accesses members through the object itself
Scope operator
Post increment operator
Post-decrement operator
(A + B)/4;
ARRAY[4] = 2;
Ptr->age = 34;
Obj.age = 34;
Class::age = 2;
for (i = 0; i <; i++) ...
for (i = ten; i > 0; i--) ...
From left to right
2 !
~
++
--
-
+
*
&
(type)
sizeof
Logical take-back operator
bitwise inverse (bitwise complement)
Predecessor increment operator
Pre-decrement operator
unary minus operator
Unary take positive operator
Dereference operator
Fetch address operator
Type conversion operators
Returns the number of bytes occupied by an object operator
if (!done) ...
Flags = ~flags;
for (i = 0; i <; ++i) ...
for (i = ten; i > 0; i.) ...
int i =-1;
int i = +1;
data = *ptr;
Address = &obj;
int i = (int) floatnum;
int size = sizeof (floatnum);
From right to left
3 ->*
.*
Operator that accesses a member on a pointer through a pointer to a member
Operator that accesses a member on an object by pointing to a pointer to a member
Ptr->*var = 24;
Obj.*var = 24;
From left to right
4 *
/
%
Multiplication operator
Division operator
Take remainder operator
int i = 2 * 4;
float F = 10/3;
int rem = 4% 3;
From left to right
5 +
-
Addition operator
Subtraction operator
int i = 2 + 3;
int i = 5-1;
From left to right
6 <<
>>
Bitwise left SHIFT operator
Bitwise RIGHT SHIFT operator
int flags = << 1;
int flags = >> 1;
From left to right
7 <
<=
>
>=
Less than comparison operators
Less than or equal to comparison operators
Greater than comparison operator
Greater than or equal to comparison operator
if (I < 42) ...
if (i <= 42) ...
if (i > 42) ...
if (i >= 42) ...
From left to right
8 ==
!=
equals comparison operator
Not equal to comparison operator
if (i = = 42) ...
if (i! = 42) ...
From left to right
9 & Bitwise AND operator Flags = flags & 42; From left to right
10 ^ Bitwise XOR OR operator Flags = flags ^ 42; From left to right
11 | Bitwise OR operator Flags = Flags | 42; From left to right
12 && Logic and operators if (Conditiona && conditionb) ... From left to right
13 || Logical OR operator if (Conditiona | | conditionb) ... From left to right
14 ? : Ternary conditional operator int i = (a > B)? A:B; From right to left
15 =
+=
-=
*=
/=
%=
&=
^=
|=
<<=
>>=
Assignment operator
Compound assignment Operator (addition)
Compound assignment operator (subtraction)
Compound assignment operator (multiplication)
Compound assignment Operator (division)
Compound assignment operator (take surplus)
Compound assignment operators (bitwise AND)
Compound assignment operator (bitwise XOR)
Compound assignment operator (bitwise OR)
Compound assignment operator (bitwise left shift)
Compound assignment operator (bitwise RIGHT SHIFT)
int a = b;
A + = 3;
B-= 4;
A *= 5;
A/= 2;
A%= 3;
Flags &= new_flags;
Flags ^= new_flags;
Flags |= new_flags;
Flags <<= 2;
Flags >>= 2;
From right to left
16 , Comma operator for (i = 0, j = 0; i <; i++, J + +) ... From left to right

Operators that cannot be overloaded

Only existing C + + operators can be overloaded in C + +, and users are not allowed to define new operators themselves!

Most of the operators in C + + can be overloaded, except for member access operators. The member pointer access operator . * , scope operator :: , length operator sizeof , and conditional operator ?: c4>;

Reference: http://www.cnblogs.com/wiessharling/p/4179753.html

C + + operator overloading

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