c++-变量,this指针,全局函数,成员函数,自定义数组类
区分变量属于哪个对象
- c++对象管理模型初探
- C++类对象中的成员变量和成员函数是分开存储的,C中内存四区仍然有效
- C++编译器对普通成员函数的内部处理(隐藏this指针)
- this指针解决函数形参和类属性相同
- 类成员函数写const,修饰的是谁?
- 全局函数 pk 类成员函数
- 类成员函数返回指针 和 返回引用
- C++类对象中的成员变量和成员函数是分开存储的,C中内存四区仍然有效
- C++编译器对普通成员函数的内部处理(隐藏this指针)
- this指针解决函数形参和类属性相同
- 类成员函数写const,修饰的是谁?
- 全局函数 pk 类成员函数
- 类成员函数返回指针 和 返回引用
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;
class Test
{
public:
Test(int i)
{
mI = i;
}
int getI()
{
//this就是指向调用改成员函数方法的对象地址
return this->mI;
//return mI;
}
private:
int mI;
};
/*
struct Test
{
int mI;
};
void Test_init(Test *pthis, int i)
{
pthis->mI = i;
}
int getI(struct Test *pthis)
{
return pthis->mI;
}
*/
int main(void)
{
Test t1(10);//Test(&t1, 10)
Test t2(20);
t1.getI();// getI(&t1)
return 0;
}
this指针
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;
class Test
{
public:
Test(int k)
{
this->m_k = k;
}
int getK() const//成员函数尾部出现const 修饰是this指针
{
//this->m_k = 100; //this指针不是 const Test *
//this++;// this指针是一个常指针, Test *const
//this->m_k = 100;
//this = this + 1;
return this->m_k;
}
//static成员函数,只能返回static成员变量
static int s_getK()
{
//return m_k;
return s_k;
}
private:
int m_k;
static int s_k;
};
int Test::s_k = 0;
int main(void)
{
Test t1(10); //Test(&t1, 10);
Test t2(20);
return 0;
}
全局函数和成员函数
如果想返回一个对象的本身,在成员方法中,用*this返回
}
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;
class Test
{
public:
Test(int a, int b)
{
this->a = a;
this->b = b;
}
void printT()
{
cout << "a = " << this->a << ", b=" << this->b << endl;
}
int getA()
{
return this->a;
}
int getB()
{
return this->b;
}
//成员方法
Test TestAdd(Test &another)
{
Test temp(this->a + another.a,this->b + another.b);
return temp;
}
//+= 方法
Test& TestAdd2(Test &another)
{
this->a += another.a;
this->b += another.b;
//this===>&t1
return *this;//如果想返回一个对象的本身,在成员方法中,用*this返回
}
private:
int a;
int b;
};
/*
//1 在全局提供一个两个Test想加的函数
Test TestAdd(Test &t1, Test &t2)
{
Test temp(t1.getA() + t2.getA(), t1.getB() + t2.getB());
return temp;
}
*/
int main(void)
{
Test t1(10, 20);
Test t2(100, 200);
//Test t3 = TestAdd(t1, t2);
Test t3 = t1.TestAdd(t2);
t3.printT();
//((t1 += t2) += t2 )+= t2
//如果相对一个对象连续调用成员方法,每次都会改变对象本身,成员方法需要返回引用。
t1.TestAdd2(t2).TestAdd2(t2);
t1.printT();
return 0;
}
自定义数组类
main.cpp
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <fstream>
#include "MyArray.h"
using namespace std;
int main(void)
{
MyArray array1(10);//开辟10元素的数组
//赋值操作
for (int i = 0; i < 10; i++) {
array1.setData(i, i + 10);
}
cout << "--------" << endl;
cout << "array1:" << endl;
for (int i = 0; i < 10; i++) {
cout << array1.getData(i) << " ";
}
cout << endl;
MyArray array2 = array1;
cout << "array2:" << endl;
for (int i = 0; i < array2.getLen(); i++) {
cout << array2.getData(i) << " ";
}
cout << endl;
MyArray array3;
array3 = array1;
cout << "array3:" << endl;
for (int i = 0; i < array3.getLen(); i++) {
cout << array3.getData(i) << " ";
}
cout << endl;
return 0;
}
Array.h
#pragma once
#include <iostream>
using namespace std;
class MyArray
{
public:
MyArray();
MyArray(int len);
MyArray(const MyArray &another);
~MyArray();
void setData(int index, int data);
int getData(int index);
int getLen();
void operator=(const MyArray& another);
private:
int len;
int *space;
};
Array.cpp
#include "MyArray.h"
MyArray::MyArray()
{
cout << "MyArray()..." << endl;
this->len = 0;
this->space = NULL;
}
MyArray::MyArray(int len)
{
if (len <= 0) {
this->len = 0;
return;
}
else {
this->len = len;
//给space开辟空间
this->space = new int[this->len];
cout << "MyArray::MyArray(int len) ..." << endl;
}
}
MyArray::MyArray(const MyArray &another)
{
if (another.len >= 0) {
this->len = another.len;
//深拷贝
this->space = new int[this->len];
for (int i = 0; i < this->len; i++) {
this->space[i] = another.space[i];
}
cout << "MyArray::MyArray(const MyArray &another) ..." << endl;
}
}
MyArray::~MyArray()
{
if (this->space != NULL) {
delete[]this->space;
this->space = NULL;
len = 0;
cout << "MyArray::~MyArray() ..." << endl;
}
}
void MyArray::setData(int index, int data)
{
if (this->space != NULL) {
this->space[index] = data;
}
}
int MyArray::getData(int index)
{
return this->space[index];
}
int MyArray::getLen()
{
return this->len;
}
void MyArray::operator=(const MyArray& another)
{
if (another.len >= 0) {
this->len = another.len;
//深拷贝
this->space = new int[this->len];
for (int i = 0; i < this->len; i++) {
this->space[i] = another.space[i];
}
cout << "MyArray::operator=(const MyArray& another) ..." << endl;
}
}
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