The static member function of class 26th

1. static member functions

(1) A static member function is a special member function in a class that belongs to the entire class.

(2) public static member functions can be accessed directly through the class name

(3) public static member functions can be accessed by object name

(4) Definition of a static member function: modifying member functions directly through the static keyword

Example of a "programming experiment" static member function

#include <stdio.h>classtest{Private:    inti; Static intS_j; Public:    intGeti (); Static voidStaticfunc (Const Char*s); Static voidStaticseti (Test&d,intv); Static intstaticgetj ();};intTest::geti () {returni;}voidTest::staticfunc (Const Char*s) {printf ("Staticfunc:%s\n", s);}voidTest::staticseti (Test&d,intv) {D.I=v; //i = V;//static member functions cannot access non-static member variablesS_j = v;//legal, accessing static member variables}intTest::staticgetj () {returnS_j;}intTest::s_j =0;intMain () {Test::staticfunc ("main Begin ...");//calling a static member function from a class nameTest t; Test::staticseti (T,Ten); printf ("t.i =%d\n", T.geti ()); printf ("S_j =%d\n", T.STATICGETJ ());//calling static member functions by object nameTest::staticfunc ("main End ...");//calling a static member function from a class name    return 0;}

2. static member functions VS ordinary member functions

	Static member functions	Ordinary member functions
All objects Shared	Yes	Yes
Implied this pointer	No	Yes
Accessing ordinary member variables/functions	No	Yes
accessing static member variables/functions	Yes	Yes
Called directly through the class name	Yes	No
The object can be directly called by the	Yes	Yes

"Programming Labs" solution

#include <stdio.h>classtest{Private:    Static intCcount; Public: Test () {ccount++;} ~test () {--Ccount;} Static intGetCount () {returnccount;}};intTest::ccount =0;intMain () {printf ("count =%d\n", Test::getcount ());//0, calling the function through the class nameTest T1;     Test T2; printf ("count =%d\n", T1.getcount ());//2, calling functions by object nameprintf"count =%d\n", T2.getcount ());//2, calling functions by object nameTest* pt =NewTest (); printf ("count =%d\n", Pt->getcount ());//3    Deletept; printf ("count =%d\n", Test::getcount ());//2, calling the function through the class name         return 0;}

3. Summary

(1) A static member function is a special member function in a class

(2) The static member function has no hidden this parameter

(3) Static member functions can be accessed directly through the class name

(4) Static member functions can only access static member variables/functions directly

The static member function of class 26th