C++中new/delete与new[]/delete[]的使用区别

#include <iostream> using namespace std; class CPoint { public: CPoint(int x = 0, int y = 0);//default constructor int SetTemp();//set m_temp value void Print(); void Print() const;//const function will not change other variables' value, and const object would call this function private: int m_x; const int m_y; static const int m_z; int m_temp; }; class CTemp { public: //CTemp(int x = 0)//the default constructor //{ // m_temp = x; //} CTemp(int x)//the definition constructor { m_temp = x; } void Print(); private: int m_temp; }; class T//test delete and delete[] { public: T() { cout<<"Constructor!"<<endl; } ~T() { cout<<"Destructor!"<<endl; } }; const int CPoint::m_z = 0;//initialize the static variable CPoint::CPoint(int x, int y):m_y(y)//m_y is a const digit member, so it should be initialized by Initialization List { m_x = x;//normal variable } int CPoint::SetTemp() { m_temp = 1; m_temp++; return m_temp; } void CPoint::Print() { cout<<"CPoint: Normal member function called: "<<endl; cout<<"m_x = "<<m_x<<"; m_y = "<<m_y<<"; m_z = "<<m_z<<"; m_temp = "<<m_temp<<endl<<endl; } void CPoint::Print() const//this function will not change other variables' value { cout<<"CPoint: Const member function called: "<<endl; cout<<"m_x = "<<m_x<<"; m_y = "<<m_y<<"; m_z = "<<m_z<<"; m_temp = "<<m_temp<<endl<<endl; } void CTemp::Print() { cout<<"CTemp: member function called: "<<endl; cout<<"m_temp = "<<m_temp<<endl<<endl; } void main() { const int Array_Size = 5; CPoint *pCPoint; pCPoint = new CPoint[Array_Size];//create 5 objects, and call the default constructor if (pCPoint == NULL)//judge whether the memory is applied successfully { cout<<"Apply for memory failed!"<<endl; exit(0); } for(int i = 0; i < Array_Size; i++) { if (i == 2) { pCPoint[i].SetTemp();//just change the third one's value } pCPoint[i].Print(); } delete []pCPoint;//release the pointer array pCPoint = NULL; CPoint *pCPointSingle = new CPoint(30, 5); pCPointSingle->Print(); delete pCPointSingle;//release single pointer CTemp *pCTemp = new CTemp(3); //CTemp *pCTemp = new CTemp[Array_Size]; if (pCTemp == NULL) { cout<<"Apply for memory failed!"<<endl; exit(0); } pCTemp->Print(); delete pCTemp;//delete the single pointer pCTemp = NULL; CPoint *pCPoint2 = new CPoint(5, 6); if (pCPoint2 == NULL) { cout<<"Apply for memory failed!"<<endl; exit(0); } delete pCPoint2; //the object behind will be freed be the SYSTEM CPoint obj_CPoint(1,1), obj_CPoint2; const CPoint const_obj_CPoint3(3,3); //const_obj_CPoint3.SetTemp();//This is wrong, because const function can not call normal function obj_CPoint.Print(); obj_CPoint2.Print(); const_obj_CPoint3.Print();//this will call the const Print() //Test for delete and delete[] cout<<"P called destructor ? times: "<<endl; T *p = new T[2];//new two objects delete p;//here is wrong, because it just call the destructor only one times cout<<endl<<endl<<"Q called destructor ? times: "<<endl; T *q = new T[2]; delete []q; }