C++ objects implement memory monitoring for new and delete interception

object_memory_monitoring - source code file - click to download

C or C language is different from other languages. It needs to manage memory by itself, and release unnecessary memory in time, otherwise it will lead to memory leakage, resulting in insufficient memory and program crash.
In C programmers, it is easy to cause memory to forget to free, especially in the case of program exceptions.
In the object, we can rewrite new and delete to achieve memory monitoring

#include <iostream>
#include <stdlib.h>

using namespace std;

class man
{
public:
    //计数器
    static int jishuqi;
    //用于指向头结点
    static man * head;
    //用于指向当前节点
    static man * local;
    man * next;
    man()
    {
        //cout << "man preject init!" << endl;
    }
    ~man()
    {
        //cout << "man preject end!" << endl;
    }
    static void * operator new(size_t size)
    {
        man *ptemp = ::new man;
        ptemp->next = NULL;
        if(head == NULL){
            head = ptemp;
        }
        if(local == NULL){
            local = ptemp;
        }
        else{
            local->next = ptemp;
            local = ptemp;
        }
        jishuqi += 1;
        cout << "man preject building! jishuqi = " << jishuqi << " address = " << ptemp << endl;
        return ptemp;
    }
    static void operator delete(void *p)
    {
        //用于指向当前节点
        man * a = head;
        //用于指向当前节点的上一个节点
        man * b = head;
        //在内存链表中查找将要删除的地址
        while(a != NULL){
            cout << "a = " << a << endl;
            cout << "b = " << b << endl;
            //查找到地址
            if( a == p ){
                //如果将要删除的地址在内存链表中是头结点
                if(a == head ){
                    //如果链表中只有一个结点，即头结点，就重新初始化链表
                    if( a->next == NULL ){
                        head = NULL;
                        local = NULL;
                    }
                    //如果链表有多个个结点，将头结点的next指向第二个结点
                    else{
                        head = a->next;
                    }
                }
                //如果将要删除的地址在内存链表中是尾结点，就将尾结点的上一个节点指向NULL，将local指针指向尾结点的上一个节点
                else if( a->next == NULL){
                    b->next = NULL;
                    local = b;
                }
                //如果将要删除的地址在内存链表中是中间节点，就被删除节点的next指针 赋值给 将被删除节点的上一个节点的next指针
                else{
                    b->next = a->next;
                }
                break;
            }
            b = a;
            //指针后移
            a = a->next;
        }
        jishuqi -= 1;
        cout << "man preject delete! jishuqi = " << jishuqi << " address = " << p << endl;
        ::delete p;
    }
    //清除所有类
    static void clean()
    {
        man * a = head;
        man * b = NULL;
        while(a != NULL){
            cout << "a = " << a << endl;
             b = a->next;
             delete a;
             a = b;
        }
    }
};

int man::jishuqi = 0;
man * man::head = NULL;
man * man::local = NULL;


void test(){
    man * wnh1 = new man;
    man * wnh2 = new man;
    man * wnh3 = new man;
    man * wnh5 = new man;
    man * wnh6 = new man;
    man * wnh7 = new man;
    man * wnh8 = new man;
    system("pause");
    cout << "测试删除头指针指向的对象 " << endl;
    delete wnh1;
    system("pause");
    man * a = wnh2->head;
    while(a != NULL){
        cout << "a = " << a << endl;
        a = a->next;
    }
    system("pause");

    cout << "测试删除中间指针指向的对象 " << endl;
    delete wnh5;
    system("pause");
    a = wnh2->head;
    while(a != NULL){
        cout << "a = " << a << endl;
        a = a->next;
    }
    system("pause");

    cout << "测试删除最后指针指向的对象 " << endl;
    delete wnh8;
    system("pause");
    a = wnh2->head;
    while(a != NULL){
        cout << "a = " << a << endl;
        a = a->next;
    }
    system("pause");

    cout << "测试删除最后指针指向的对象重新创建对象时，local指针指向是否正常 " << endl;
    man * wnh9 = new man;
    system("pause");
    a = wnh2->head;
    while(a != NULL){
        cout << "a = " << a << endl;
        a = a->next;
    }
    system("pause");

    cout << "测试删除全部对象后，head和local指针指向是否正常 " << endl;

    man::clean();
    //delete wnh2;
    //delete wnh3;
    //delete wnh6;
    //delete wnh7;
    //delete wnh9;
    system("pause");
    man * wnh10 = new man;
    system("pause");
    a = wnh2->head;
    while(a != NULL){
        cout << "a = " << a << endl;
        a = a->next;
    }
    system("pause");
}

int main()
{
    test();
    system("pause");
    return 0;
}

result

man preject building! jishuqi = 1 address = 001978D0
man preject building! jishuqi = 2 address = 00197900
man preject building! jishuqi = 3 address = 00197930
man preject building! jishuqi = 4 address = 00197990
man preject building! jishuqi = 5 address = 001979C0
man preject building! jishuqi = 6 address = 001979F0
man preject building! jishuqi = 7 address = 00197A20
请按任意键继续. . .
测试删除头指针指向的对象
a = 001978D0
b = 001978D0
man preject delete! jishuqi = 6 address = 001978D0
请按任意键继续. . .
a = 00197900
a = 00197930
a = 00197990
a = 001979C0
a = 001979F0
a = 00197A20
请按任意键继续. . .
测试删除中间指针指向的对象
a = 00197900
b = 00197900
a = 00197930
b = 00197900
a = 00197990
b = 00197930
man preject delete! jishuqi = 5 address = 00197990
请按任意键继续. . .
a = 00197900
a = 00197930
a = 001979C0
a = 001979F0
a = 00197A20
请按任意键继续. . .
测试删除最后指针指向的对象
a = 00197900
b = 00197900
a = 00197930
b = 00197900
a = 001979C0
b = 00197930
a = 001979F0
b = 001979C0
a = 00197A20
b = 001979F0
man preject delete! jishuqi = 4 address = 00197A20
请按任意键继续. . .
a = 00197900
a = 00197930
a = 001979C0
a = 001979F0
请按任意键继续. . .
测试删除最后指针指向的对象重新创建对象时，local指针指向是否正常
man preject building! jishuqi = 5 address = 00197A20
请按任意键继续. . .
a = 00197900
a = 00197930
a = 001979C0
a = 001979F0
a = 00197A20
请按任意键继续. . .
测试删除全部对象后，head和local指针指向是否正常
a = 00197900
a = 00197900
b = 00197900
man preject delete! jishuqi = 4 address = 00197900
a = 00197930
a = 00197930
b = 00197930
man preject delete! jishuqi = 3 address = 00197930
a = 001979C0
a = 001979C0
b = 001979C0
man preject delete! jishuqi = 2 address = 001979C0
a = 001979F0
a = 001979F0
b = 001979F0
man preject delete! jishuqi = 1 address = 001979F0
a = 00197A20
a = 00197A20
b = 00197A20
man preject delete! jishuqi = 0 address = 00197A20
请按任意键继续. . .
man preject building! jishuqi = 1 address = 00197A20
请按任意键继续. . .
a = 00197A20