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C/C++ code:

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h> /*°üº¬Í·Îļþ¡£*/
main()
{
int fd,fd2,size,i=1;
char path[]="/root/s.txt"; /*Òª´ò¿ªµÄÎļþ¡£*/
char newpath[]="/root/a2.txt"; /*¸´ÖƵÄĿ¼Îļþ¡£*/
char buf[100]; /*¶¨ÒåÒ»¸ö×Ö·û´®¡£*/
extern int errno; /*¶¨ÒåÒ»¸ö´íÎóºÅ¡£*/
fd=open(path,O_RDONLY); /*´ò¿ªÔ´Îļþ¡£*/
fd2=open(newpath,O_WRONLY|O_CREAT); /*´ò¿ªÄ¿±êÎļþ¡£*/
if(fd!=-1)
{
printf("opened file %s .\n",path); /*Ô´Îļþ´ò¿ª³É¹¦¡£*/
}
else
{
printf("cant't open file %s.\n",path); /*Ô´Îļþ´ò¿ªÊ§°Ü¡£*/
printf("errno:%d\n",errno); /*ÏÔʾ´íÎóºÅ¡£*/
printf("ERR :%s\n",strerror(errno)); /*ÏÔʾ´íÎóÐÅÏ¢¡£*/
}
for(;i!=0;)
{
i=read(fd,buf,sizeof(buf)); /*´ÓÔ´ÎļþÖжÁÈ¡ÄÚÈÝ¡£*/
printf("%d",i); /*Êä³ö¶ÁÈ¡µÄ×Ö½Ú¸öÊý¡£*/
printf("%s",buf); /*Êä³öÄÚÈÝ¡£*/
if(i==-1) /*µ½´ïĩβÔò½áÊø¡£*/
{
break; /*½áÊøÑ­»·¡£*/
}
else
{
write(fd2,