char *p; p++ ; p位移加sizeof(char) 1;
int *p ; p++; p位移加sizeof(int) 4;
double *p; p++ p位移加sizeof(double)8;
truct sdshdr {
unsigned int len;
unsigned int free;
char *buf;
};
truct sdshdr * p; p++; p位移加上sizeof(truct sdshdr) 12;