C + + 11-stl-function object (ON)

1. Definition

In STL, the function can be passed to the algorithm, or the function object can be passed to the algorithm.

So, what is a function object?

Let's take a look at its statement:

class x{public:  //  define function call operator  return operator Const ;  ...}

You can call this:
X fo;

...

Fo (arg1, arg2);

Let's look at a simple print example

PrintInt.h

#ifndef        Print_int_h_#define        print_int_h_<iostream>usingnamespace std; class Printint {public:    voidoperator() (int  Const     {        ';    }}; #endif

FuncObjectTest.h

#ifndef Stl_alg_func_object_test_h_#defineStl_alg_func_object_test_h_#include".. /.. /testbase.h"classFuncobjecttest: Publictestbase{ Public: Funcobjecttest (Const string&c,Const string&d): Testbase (c, D) {}voidrun ();Private:    voidprintfuncobject ();};#endif

FuncObjectTest.cpp

#include <vector>#include<algorithm>#include<iostream>#include"FuncObjectTest.h"#include".. /.. /core/printint.h"using namespacestd;voidfuncobjecttest::p rintfuncobject () {vector<int>Coll; //insert elements from 1 to 9     for(inti =1; I <=9; ++i) {coll.push_back (i); }    //Print all elementsFor_each (Coll.cbegin (), Coll.cend (),//RangePrintint ());//Operationcout <<Endl;}voidFuncobjecttest::run () {Printstart ("Printfuncobject ()");    Printfuncobject (); Printend ("Printfuncobject ()");}

Operation Result:

----------------Printfuncobject (): Run Start----------------
1 2 3 4 5 6 7 8 9
----------------Printfuncobject (): Run End----------------

C + + 11-stl-function object (ON)