指针运算符
(1)指针+1的表示含义:加一个单元格
(2)指针+数字:需要调整,调整的权重为sizeof(指针去掉一个*)
(3)指针-数字:需要调整,调整的权重为sizeof(指针去掉一个*)
(4)指针+指针:不可以。错误操作
(5)指针-指针:表示之间间隔的单元格数(有正负之分,表示谁的地址大谁的地址小)
算出字节数
除以调整的权重
总结:指针的所有算术运算符都需要调整,调整的权重为sizeof(指针去掉一个*)
如下例子:
指针加法:
int *p = (int *)2000;
printf("%d\n",p+4); //2016
printf("%d\n",(short *)p+4); //2008
printf("%d\n",(double *)p+4); //2032
printf("%d\n",(float **)p+4); //2016
printf("%d\n",(unsigned short *)p+4); //2008
printf("%d\n",(long *)p+4); //2016
printf("%d\n",(char *)p+4); //2004
printf("%d\n",(unsigned long long)p+4);//2004
指针减法:
int *p = (int *)0x2010;
printf("%x\n",p-2); //2008
printf("%x\n",(short *)p-2); //200c
printf("%x\n",(unsigned long *)p-2); //2008
printf("%x\n",(long long **)p-2); //2008
printf("%x\n",(float *)p-2); //2008
printf("%x\n",(double *)p-2); //2000
printf("%x\n",(char *)p-2); //200e
printf("%x\n",(unsigned long)p-2); //200e
在计算的过程中,要特别注意指针是4字节,进行调整时,只对有指针的进行调整。