1. operator new在无法完成内存分配请求时会抛出异常（在以前或者某些特定情况（声明nothrow）下new会返回0）

2. 使用C语言的宏定义处理会是这样

#define NEW(PTR, TYPE)							\	try {(PTR) = new TYPE; }					\	catch (std::bad_alloc&) { assert(0); }

3. 用C++的异常处理机制，处理方法是这样

#include 
    
     #include 
     
      using namespace std;/*#define NEW(PTR, TYPE)							\	try {(PTR) = new TYPE; }					\	catch (std::bad_alloc&) { assert(0); }*///new异常处理模版类template 
      
       class NewHandlerSupport{public:	static new_handler set_new_handler(new_handler handler);	static void* operator new(size_t size);private:	static new_handler current_handler;};//设置异常处理函数template 
       
        new_handler NewHandlerSupport
        
         ::set_new_handler(new_handler handler){	new_handler old_handler = current_handler;	current_handler = handler;	return old_handler;}//重写newtemplate
         
          void* NewHandlerSupport
          
           ::operator new(size_t size){ void* memory = NULL; new_handler old_handler = ::set_new_handler(current_handler); try { memory = ::operator new(size); } catch (std::bad_alloc&) { set_new_handler(old_handler); throw; } set_new_handler(old_handler); return memory;}//初始化静态数据template
           
            new_handler NewHandlerSupport
            
             ::current_handler;//具体类继承模版实例class Example : public NewHandlerSupport
             
              {public: //...private: //...};int main(){ Example* e = new Example; return 0;}
             
            
           
          
         
        
       
      
     
    

4. 如果想让new分配失败不抛出异常而是返回0，可以像下面这样

int* i = new (nothrow) int;