C ----memcpy memmove

#include<stdio.h>
#include<stdlib.h>
#include<memory.h>
void* my_memcpy(void* dest, void* src, int count)
{
  char *my_dest = (char*)dest;
  char *my_src = (char*)src;
  if(dest == NULL || src == NULL)
  {  
    return NULL;
  }
  while(count--)
  {
    *my_dest++ = *my_src++;
  }
  return dest;
}
int main()
{
  char str[] = "helloworld";
  char str1[] = "helloworld";
  char str2[] = "helloworld";
  char str3[]= "helloworld";
  char str4[]= "helloworld";
  char *dest, *src;
  int i = 1;
  src = str;
  dest = &str[2];
  for(i; i <= 5; i++)
  {
    *dest++ = *src++;
  }
  memcpy(&str1[2],str1,5);
  memmove(&str2[2],str2,5);
  strncpy(&str3[2],str3,5);
  my_memcpy(&str4[2],str4,5);
  printf("local for loop:%s\n",str);
  printf("memcpy:%s\n",str1);
  printf("memmove:%s\n",str2);
  printf("strncpy:%s\n",str3);
  printf("my_memcpy:%s\n",str4);
  return 0;
}

mali@mali:~/Code/my_work$ gcc test_memmove.c -o test_memmove
mali@mali:~/Code/my_work$ ./test_memmove 
local for loop:hehehehrld
memcpy:hehelllrld
memmove:hehellorld
strncpy:hehellorld
my_memcpy:hehehehrld

 

来源：CSDN

作者：merry1996

链接：https://blog.csdn.net/merry1996/article/details/91437589