qsort和memset

总是忘了 怎么用，放在这吧，以后好找

------qsort--------

int cmp ( const void *a , const void *b ) {
    return *(int *)a - *(int *)b;
}

sample:qsort(num,100,sizeof(num[0]),cmp);

 

-----memset--------

memset(num,0,sizeof(num[0])*100);