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数据加载中……

重载全局运算符new与delete

一、
读程序：
#include<stdio.h>
#include<malloc.h>
void* operator new(unsigned bytes)
{
    printf("SELF-GLOBAL-operator new!bytes=%d\n",bytes);
    void* pvTemp=malloc(bytes);
    return pvTemp;
}
void operator delete(void *pvMem)
{
    printf("SELF-GLOBAL-operator delete\n");
    free(pvMem);
}
class claA
{
    int dat[5];
    public:
    claA()
    {
        printf("claA::claA()!\n");
    }
    ~claA()
    {
        printf("claA::~claA()!\n");
    }
};
int main()
{
    int *pi=new int(123);
    delete pi;
    claA *pmyCla=new claA;
    delete pmyCla;
    claA* pmyClaA=new claA[2];
    delete []pmyClaA;
    return 0;
}

输出结果为：
SELF-GLOBAL-operator new!bytes=4
SELF-GLOBAL-operator delete
SELF-GLOBAL-operator new!bytes=20
claA::claA()!
claA::~claA()!
SELF-GLOBAL-operator delete
SELF-GLOBAL-operator new!bytes=44
claA::claA()!
claA::claA()!
claA::~claA()!
claA::~claA()!
SELF-GLOBAL-operator delete

二、
读程序：
#include<stdio.h>
#include<string.h>
#include<process.h>

#define MAX_SIZE 10000
static char MemArea[MAX_SIZE];
static char*pm=MemArea;

void* operator new(unsigned bytes)
{
    printf("SELF-GLOBAL-operator new!bytes=%d\n",bytes);
    if(pm+bytes<=MemArea+MAX_SIZE)
    {
        pm+=bytes;
        return (void*)(pm-bytes);
    }
    else
    {
        printf("My-new-fail!I only have %d bytes memory now!",MemArea+MAX_SIZE-pm);
        printf(" but you need %d bytes~\n",bytes);
        return NULL;
    }
}
void operator delete(void *pvMem)
{
    printf("SELF-GLOBAL-operator delete!\n");
    if((char*)pvMem>=MemArea&&(char*)pvMem<MemArea+MAX_SIZE)
    pm=(char*)pvMem;
}
int main()
{
    char *pc=(char*)new char[MAX_SIZE];
    strcpy(pc,"1234567abcdefg");
    printf("pc=>%s\n",pc);
    delete pc;
    double *pd=(double*)new double(862.13);
    printf("%d\n",sizeof(double));
    printf("(*pd)=%f\n",*pd);
    double* pdA1=(double*)new double[10];
    delete[]pdA1;
    double* pdA2=(double*)new double[1250];
    if(!pdA2)
    {
        delete pd;
    }
    delete[]pdA2;
    delete pd;
    return 0;
}
输出结果为：
SELF-GLOBAL-operator new!bytes=10000
pc=>1234567abcdefg
SELF-GLOBAL-operator delete!
SELF-GLOBAL-operator new!bytes=8
8
(*pd)=862.130000
SELF-GLOBAL-operator new!bytes=80
SELF-GLOBAL-operator delete!
SELF-GLOBAL-operator new!bytes=10000
My-new-fail!I only have %d bytes memory now! but you need 9992 bytes~
SELF-GLOBAL-operator delete!
SELF-GLOBAL-operator delete!

posted on 2009-08-22 18:22 八路 阅读(573) 评论(0)  编辑 收藏 引用 所属分类: 学习笔记


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