C++的自动内存管理

内存泄漏问题，过去在C语言曾是一个令人头痛的问题。但在C++却可以自动的管理。方法就是重载全局的new，在分配一个对象的时候，同时把它的内存地址挂在一个zone上。

#include <stdio.h>
#include <string.h>

struct zone {
    
    
        struct link {
    
    
                struct link *p;

                template <typename T>
                T *data() {
    
    
                        return (T*) (&this[1]);
                }
        } list;

        void free();
        template <typename T>
        void free();
}z;

void zone::free()
{
    
    
        struct link *p;
        p = list.p;
        while (p) {
    
    
                list.p = p->p;
                delete p;
                p = list.p;
        }
}
template <typename T>
void zone::free()
{
    
    
        struct link *p;
        T *data;
        p = list.p;
        while (p) {
    
    
                data = p->data<T>();
                data->~T();
                list.p = p->p;
                delete p;
                p = list.p;
        }
}

void *operator new(size_t size, zone &z)
{
    
    
        void *p = operator new(size +sizeof(zone::link));
        zone::link *node;
        node = (zone::link *)p;
        node->p = z.list.p;
        z.list.p = node;
        return (void*)((char*)p+sizeof(zone::link));
}

struct node {
    
    
        char name[10];
        int val;
        ~node() {
    
    printf("destroy-node (%s: %d)\n", name,val);}
};


int main()
{
    
    
        node *a, *b, *c, *p;
        a = new(z) node;
        strcpy(a->name,"Alice.a");
        a->val = 100;
        b = new(z) node;
        strcpy(b->name,"Bob.b");
        b->val = 99;

        c = new(z) node;
        strcpy(c->name,"Carl.c");
        c->val = 98;

        zone::link *q = z.list.p;
        while(q) {
    
    
                p = q->data<node>();
                printf("[*] %s: %d\n", p->name, p->val);
                q = q->p;
        }
        z.free<node>();
}

这里重载了new，怎么没有重载delete? 不必如此，因为根本用不到它。