CString.hpp

#include <iostream>
#include <string.h>#pragma warning(disable:4996)
using namespace std;class CString {
private:int len;char* data;public:CString():data(nullptr),len(0) {cout << "0空构造\n";}CString(const char* _data) {if (!_data) {len = 0;data = new char(1);*data = '\0';cout << "1空构造\n";}else {len = (int)strlen(_data);data = new char[strlen(_data) + 1];memset(data, 0, len + 1);strcpy(data, _data);cout << "char*构造\n";}}const char* getValue() const {return data;}int getLength() const{return len;}CString (const CString& str){len = str.getLength();data = new char[len+1];memset(data, 0, len + 1);strcpy(data, str.getValue());cout << "str构造\n";}CString& operator=(const CString & str){if (this == &str) {return *this;}len = str.getLength();delete[] data;data = new char[len + 1];strcpy(data, str.getValue());return *this;}CString operator+(const CString &str) const{CString nstr;nstr.len = this->len + str.getLength();nstr.data = new char[nstr.len + 1];strcpy(nstr.data, (*this).data);strcat(nstr.data, str.getValue());return nstr;}~CString() {delete[] data;}};class String {
private:char* data; // 存储字符数组的指针
public:String(const char* str = "") : data(new char[strlen(str) + 1]) {strcpy(data, str);}~String() {delete[] data;}const char* getData() const {return data;}
};

Shape.hpp

#include<iostream>class Shape {
public:virtual double printArea() = 0;
};class Circle :public Shape {
private:double r;
public:Circle(double _r) { r = _r; }virtual double printArea() {return r * r * 3.14159;}
};class Rectangle :public Shape {
private:double w, h;
public:Rectangle(double _w, double _h) { w = _w; h = _h; }virtual double printArea() {return w * h;}
};class Triangle :public Shape {
private:double w, h;
public:Triangle(double _w, double _h){w = _w;h = _h;}virtual double printArea() {return w * h /2;}
};

cmain.cpp

#include "CString.hpp"
#include "Shape.hpp"
#include <vector>int main() 
{
#if 1CString s1("123");CString s2(s1);CString s3 = s1 + s2;CString s4;s4 = s3;cout << s4.getLength() << "," << s4.getValue() << endl;vector<Shape*> ss;Shape* c = new Circle(2.1);Shape* r = new Rectangle(4, 5);Shape* t = new Triangle(4,2);ss.push_back(c);ss.push_back(r);ss.push_back(t);for (auto v = ss.begin(); v != ss.end(); v ++) {cout<< "area:" << (*v)->printArea() << endl;Shape* ptr = *v;delete ptr;ptr = nullptr;}ss.erase(ss.begin(), ss.end());
#endifreturn 0;
}