linux下的简单c 语言程序 求助

[pshlcysz]

#include "stdio.h"
#include "stdlib.h"
#include "fcntl.h"
#include "sys/types.h"
#include "sys/stat.h"

int main(void){
int fp1,fp2;
int size;
char buffer[80];
if((fp1=open("abc.txt",O_RDONLY))<0){
printf("this file is not exit!");
exit(0);
}
if((fp2=open("cd.txt",O_WRONLY|O_CREAT))<0){
printf("overflow!");
exit(0);
}
while(fp1!=-1){
size=read(fp1,buffer,sizeof(buffer));
write(fp2,buffer,size);
}
close(fp1);
close(fp2);
}


这是我写的c语言程序 因为对linux不是很熟悉 所以也不是很清楚 到底哪里需要修改 请各位大侠指点

[AnYidan]

什么问题？

[pshlcysz]

[Quote=引用 1 楼 anyidan 的回复:]
什么问题？
[/Quote]

执行的时候显示：permission denied

那个我在头文件里加了#include "unistd.h"

[Sun_Phoenix]

#include "stdio.h"//用双引号干什么<stdio.h>
#include "stdlib.h"
#include "fcntl.h"
#include "sys/types.h"
#include "sys/stat.h"

int main(void){
  int fp1,fp2;
  int size;
  char buffer[80];

  if((fp1 = open("abc.txt", O_RDONLY)) < 0){
       printf("this file is not exit!");
       exit(0);//exit(1);0一般表示正确
   }
  //加O_CREAT需要加mode
  if((fp2=open("cd.txt", O_WRONLY |O_CREAT| O_TRUNC, 0666))<0){
      printf("overflow!");
      exit(0);//同上
   }
  //不要这个了while(fp1 != -1)
  while ((size=read(fp1, buffer, sizeof(buffer)) > 0){
      if (write(fp2, buffer, size) != size)) {
           perror("write error");
      }
  }

  close(fp1);
  close(fp2);
}

不知道对不对！改了下

[pshlcysz]

I have already changed the program like follows,but it always display the information :overflow when I execute the program. Is there anyone who can tell me why ? Thank you ! Because now I am working in Linux and the languages is English ,I have to tell you the problem in English.please forgive me !


#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

int main(void){
int fp1,fp2;
int size;
char buffer[80];
if((fp1=open("abc.txt",O_RDONLY))<0){
printf("abc.txt is not exit!");
exit(0);
}
if((fp2=open("cd.txt",O_WRONLY|O_CREAT,0666))<0){
printf("overflow!");
exit(0);
}
while(fp1>0){
size=read(fp1,buffer,sizeof(buffer));
write(fp2,buffer,size);
}
close(fp1);
close(fp2);
printf("ending");
return 1;
}

[「已注销」]

size=read(fp1,buffer,sizeof(buffer));
write(fp2,buffer,size);

read 为什么是读sizeof(buffer)，应该是去读80，buffer的大小，而不是buffer type的大小。

[「已注销」]

while(fp1>0)

fp1是大于0的，不是死循环了么

[yyysss520]

permission denied 找个是权限问题啊 你切成root用户

[dreamer_shax]

[Quote=引用 5 楼 ncu571633 的回复:]

size=read(fp1,buffer,sizeof(buffer));
write(fp2,buffer,size);

read 为什么是读sizeof(buffer)，应该是去读80，buffer的大小，而不是buffer type的大小。
[/Quote]

sizeof（数组名）就是该数组的大小。

[pshlcysz]

I have already changed the program as follows,but it still display the message:overflow

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

int main(void){
int fp1,fp2;
int size;
char buffer[80];
if((fp1=open("abc.txt",O_RDONLY))<0){
printf("abc.txt is not exit!");
exit(1);
}
if((fp2=open("cd.txt",O_WRONLY|O_CREAT,00700))<0){
printf("overflow!\n");
exit(1);
}
while((size=read(fp1, buffer, sizeof(buffer)) ) > 0){
if((write(fp2,buffer,size))!=size){
perror("write error");
};
}
close(fp1);
close(fp2);
printf("ending");
return 1;
}

[jianghandaxue]

[Quote=引用 4 楼 pshlcysz 的回复:]
I have already changed the program like follows,but it always display the information :overflow when I execute the program. Is there anyone who can tell me why ? Thank you ! Because now I am working i……
[/Quote]



UP

[W170532934]

为什么我在fedore下怎么没有错？？？

[pshlcysz]

好了 朋友们 我的问题解决了 我最后一次贴出的程序无误 主要是没有权限 像上面一个朋友说的 切换到root 就Ok了 谢谢诸位