const char * IND(const char * str, const char * substr)
{
assert(substr != NULL && str != NULL);
const char * psub = substr;
const char * pstr = str;
while (*pstr)
{
const char * tmp = pstr;
while (*tmp++ == *psub++);
if (*psub == '\0')
return pstr;
psub = substr;
pstr++;
}
return NULL;
}
为什么要
const char * psub = substr;
const char * pstr = str;
const char * tmp = pstr;
而不是直接操作