对memcpy函数的改进

void *mymemcpy(void *dst,const void *src,size_t num)
{
    assert((dst!=NULL)&&(src!=NULL));
    int wordnum = num/4;//计算有多少个32位，按4字节拷贝
    int slice = num%4;//剩余的按字节拷贝
    int * pintsrc = (int *)src;
    int * pintdst = (int *)dst;
    while(wordnum--)*pintdst++ = *pintsrc++;
    while (slice--)*((char *)pintdst++) =*((char *)pintsrc++);
    return dst;
}