C学习笔记：memcpy与memmove函数探索

#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
void my_memcpy(void* des,const void* src,size_t k)
{
	while (k--)
	{
		*(char*)des = *(char*)src;
		++(char*)src;
		++(char*)des;
	}	
}
void* my_memmove(void* des, void* src,size_t count)
{
	const char* p = src;
	if (src > des)
	{
		while (count--)
		{
			*(char*)des = *(char*)src;
			++(char*)src;
			++(char*)des;
		}
	}
	else
	{
		while (count--)
		{
			*((char*)des + count) = *((char*)src + count); //倒序交换,count从19开始
		}
	}
	return p;
}
int main()
{
	int arr1[] = { 1,2,3,4,5,6,7,8,9,10 };
	int arr2[10] = { 0 };
	//my_memcpy(arr2, arr1, sizeof(arr1));
	void* ret = my_memmove(arr1+2, arr1,20);
	for(int i =0;i<10;printf("%d ",arr1[i++]));
	return 0;
}