内存重叠拷贝函数
 
#include<stdio.h>
#include<assert.h>
 
void my_memmove(void *p1,void const *p2,size_t count)
{  
    char *dest = (char *)p1;
    char *src = (char *)p2;
    assert(p1);
    assert(p2);
 
    if((dest > src) && (dest < src +count))
    {
        while(count--)
        {
            *(dest + count) = *(src + count); 
        }
    }
    else
    {
        while(count--)
        {
            *dest++ = *src++;
        }
    return p1;
    }
}
 
int main()
{
    int arr1[10]={1,2,3,4,5,6,7,8,9,10};
    int i = 0;
    my_memmove(arr1+4,arr1+2,16);
    for(i=0;i<10;i++)
    {
        printf("%d ",arr1[i]);
    }
    printf("\n");
    return 0;
}