C库中的memmove()函数的实现

#include <stdio.h>#include <iostream>#include <string.h>using namespace std;void* mymemmove(void* dest, const void* src, const size_t count){if (0 == count){return NULL;}if (NULL == dest || NULL == src){return NULL;}char* psrc = (char*)src;char* pdest = (char*)dest;if (pdest <= psrc || pdest > psrc + count)//没有覆盖的情况{cout << "overlapping" << endl;for (size_t i = 0; i < count; i++){*pdest = *psrc;pdest++;psrc++;}}else//覆盖的情况{pdest = pdest + count;psrc = psrc + count;for (size_t i = 0; i < count; i++){pdest--;psrc--;*pdest = *psrc;}}return dest;}

当复制片段没有重复的时候memmove和memcpy相同