实现memmove
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<assert.h>
void *my_memmove(void *dest, const void *src, size_t count)
{
char *ret = NULL;
char *pdest = (char *)dest;
char *psrc = (char *)src;
ret = dest;//转化成指针类型
assert(dest);
assert(src);
if ((pdest<psrc + count) && (pdest>psrc))//从后往前拷贝
{
while (count--)
{
pdest[count] = psrc[count];
//*(pdest+count)=*(psrc+count);
}
}
else //从前往后拷贝
{
while (count--)
{
*(pdest++) = *(psrc++);
}
}
return ret;
}
int main()
{
int i = 0;
int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
my_memmove(arr + 3, arr + 1, 4 * 4);
for (i = 0; i < sizeof(arr) / sizeof(arr[0]); i++)
{
printf("%d ", arr[i]);
}
printf("\n");
system("pause");
return 0;
}运行结果：
1 2 3 2 3 4 5 8 9
请按任意键继续. . .
