Object-oriented Programming-c++ Operator overloading & Type conversion (Static) "11th class notes"

This class continues to explain the [], and other specific examples of operator overloading

A case of type conversion for a class of a single parameter of C + + is also explained

Finally, the third function of static is mentioned slightly: data members at rest

I have commented on the details, we can look at it slowly.

Any questions can be in this article under the message I will promptly answer:)

#include <iostream>#include<cmath>using namespacestd;classMyArray {Private:    float*p; unsignedintsize; Public: MyArray (unsignedintLen =0); ~MyArray (); unsignedintGetSize ()Const; DoubleMoudar ()Const; Const float&operator[] (intIndexConst;//Subscript operators can only be overloaded in member functions    float&operator[] (intindex);//Only member function};myarray::myarray (unsignedintLen) {    float* TMP =New float[Len]; if(NULL = = tmp) {//Check whether new work OKcout <<"memory allocation error!"<<Endl; P=NULL; Size=0; } Else{p=tmp; Size=Len;  for(inti =0; i < Len; ++i) {P[i]=0.0f; }}}myarray::~MyArray () {if(NULL! =p) {delete [] p; Size=0; } P= NULL;//ensure that the P pointer is empty after the destruction}unsignedintMyarray::getsize ()Const {    returnsize;}DoubleMyarray::moudar ()Const {    //float sum = 0.0f;    Doublesum =0.0;  for(inti =0; i < size; ++i) {floatA =P[i]; Sum+ = A *A; } Sum=sqrt (sum); returnsum;}Const float& MyArray::operator[] (intIndexConst {    returnP[index];}float& MyArray::operator[] (intindex) {    returnP[index];} Ostream&operator<< (Ostream & out,ConstMyArray &Ma) {    intSize =ma.getsize ();  out<<"{";  for(inti =0; I < size-1; ++i) { out<< Ma[i] <<", "; }     out<< Ma[size-1] <<"}"<<Endl; return  out;}intMain () {MyArray MA (4);//init one object    DoubleLength =Ma.moudar (); floatelement = ma[2];//Get The elementma[3] =12.5f;//Update the element valuema[0] =3.8f; cout<< Ma << Endl;//!! Only Golbal function    return 0;}

//= () []->* only overloaded by member function//<< When the output is expressed, it can only be overloaded as a global function, and when the shift operation is expressed,#include<iostream>using namespacestd;classMyclassa { Public:    inti; Myclassa (intK = $): I (k) {cout <<"Myclassa Init"<<Endl;};} ;classMYCLASSB {//Class B is responsible for creating a child object, and if nothing is written, it is with the default//constructor is created, otherwise it needs to be written in the member initialization list Public:    intm;                Myclassa A; //object member, when a B object is created, the A object is constructed firstMyclassa *operator- (); //MYCLASSB * operator ();MYCLASSB (intJ): A (j), M (Ten) {cout <<"MYCLASSB Init"<<Endl;};} ;/*MYCLASSB * myclassb::operator-> () {cout << "Myclassb * myclassb::operator-> ()" << Endl; return this;}*/Myclassa* MYCLASSB::operator-() {cout<<"Myclassa * myclassb::operator-> ()"<<Endl; return&A;}intMain () {MYCLASSB B ( at); cout<< B->i <<Endl; //cout << b->m << Endl;    return 0;}

//type conversion of a class for a single parameter of C + +//Conversion of Classes#include<iostream>using namespacestd;//class A;classInteger {inti; //A; Public:    //explicit: Tell the compiler that if you want to convert, it must be an explicit        ExplicitInteger (intK =0): I (k) {cout <<"Integer (int k = 0)"<<Endl;} Integer&operator= (ConstInteger &obj); Friend Ostream&operator<< (Ostream & out,ConstInteger &ing); //operator A () {return A;}    Explicit operator int() {returnI }//type conversion function    Explicit operator Double() {returni +45.51; }//type conversion function};ostream&operator<< (Ostream & out,ConstInteger &ing) {     out<< ing.i <<Endl; return  out;} Integer& Integer::operator= (ConstInteger &obj) {    if( This= = &obj)return* This;//Check self-assigned valuei =obj.i; cout<<"operator = (const Integer & obj)"<<Endl; return* This;}intMain () {Integer A ( $), B; b= Integer ( the); cout<< b <<Endl; intm =int(b);//convert an integer type to reshapecout << M <<Endl; DoubleD =Double(b); cout<< D <<Endl; return 0;}

//static data member#include<iostream>using namespacestd;classInteger {//static int i;    Static intNumber//the entire class has only one version, all objects are shared Public: Integer (intK =0) { ++Number ;} Static intGetNumber ()Const{returnNumber ;}};intInteger::number =0;intMain () {Integer Zhao, Jin, Wei, Shi, Tian, Cai; cout<< Zhao.getnumber () <<Endl; cout<< Integer::getnumber () <<Endl; return 0;}

Object-oriented Programming-c++ Operator overloading & Type conversion (Static) "11th class notes"