c memcpy function to achieve

void *memcpy(void* memTo, const void* memFrom, size_t size)
{
	assert((memTo != NULL)&&(memFrom != NULL)); //memTo和memFrom必须有效

	char* tempFrom = (char*)memFrom; //保存memFrom首地址
	char* tempTo = (char *)memTo;//保存memTo首地址

	while (size-- > 0)
	{
		*tempTo++ = *tempFrom++;
	}

	return memTo;
}

int main()
{
	char strSrc[] = "Hello world!";
	char strDest[20];

	memcpy(strDest,strSrc,sizeof(strSrc)/sizeof(*strSrc)+1);

	printf("strDest：%s\n", strDest);
	system("pause");
	return 0;
}