首页 > 代码库 > 走进C++程序世界-----operator new delete 重载
走进C++程序世界-----operator new delete 重载
在C++ 的世界里，new 和delete 是关键字，而在C的世界里相对应的malloc和free是函数，关键C++的new和delete分析，详见前面的章节，这里就不在过多的介绍了。链接。
下面来研究下关于new 和delete的重载。
1、对比使用重载和未使用重载
未使用“/*File : operator_new.cpp
*Auth : sjin
*Date : 2014-04-27
*Mail : 413977243@qq.com
*/
#include <iostream>
using namespace std;
class test {
public:
test(){cout << "*****构造test()*****"<< endl;};
~test(){cout << "+++++析构test()+++++"<< endl;};
};
int main()
{
test * x = new test;//执行分配空间，再执行析构函数
delete x;//先执行析构函数，在释放空间
}
使用重载后，
/*File : operator_new.cpp
*Auth : sjin
*Date : 2014-04-27
*Mail : 413977243@qq.com
*/
#include <iostream>
using namespace std;
char mem[10000] = {‘\0‘};
int pos = 0;
class test {
public:
test(){cout << "*****构造test()*****"<< endl;};
~test(){cout << "+++++析构test()+++++"<< endl;};
public:
void * operator new(size_t bytes){
cout << "------new test()------" << endl;
int alloc = pos;
pos += bytes;
return (mem + alloc);
};
void operator delete(void *){
cout << "------delete test()------" << endl;
};
};
int main()
{
test * x = new test;
delete x;
}/*File : operator_new.cpp
*Auth : sjin
*Date : 2014-04-27
*Mail : 413977243@qq.com
*/
#include <iostream>
using namespace std;
char mem[10000] = {‘\0‘};
int pos = 0;
class test {
public:
test(){cout << "*****构造test()*****"<< endl;};
~test(){cout << "+++++析构test()+++++"<< endl;};
public:
void * operator new(size_t bytes){
cout << "------new test()------" << endl;
int alloc = pos;
pos += bytes;
return (mem + alloc);
};
void operator delete(void *){
cout << "------delete test()------" << endl;
};
};
int main()
{
test * x = new test;
delete x;
x = new test[3];
delete [] x;//这里对数组释放，需要注意
}
#include <iostream>
using namespace std;
char mem[10000] = {‘\0‘};
int pos = 0;
class test {
public:
test(){cout << "*****构造test()*****"<< endl;};
~test(){cout << "+++++析构test()+++++"<< endl;};
public:
void * operator new(size_t bytes){
cout << "------new test()------" << endl;
int alloc = pos;
pos += bytes;
return (mem + alloc);
};
void operator delete(void *){
cout << "------delete test()------" << endl;
};
void * operator new[](size_t bytes){
cout << "------new test()------" << endl;
int alloc = pos;
pos += bytes;
return (mem + alloc);
};
void operator delete[](void *){
cout << "------delete test()------" << endl;
};
};
int main()
{
test * x = new test;
delete x;
x = new test[3];
delete [] x;
}
对new 和delete 函数的重载可以用来检测 内存泄露的情况。
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。