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Linux教程網 >> Linux基礎 >> Linux教程 >> Linux文件操作函數open close read write等示例

Linux文件操作函數open close read write等示例

日期:2017/2/28 16:25:26   编辑:Linux教程

//fileopen.c

#include<stdio.h>

#include<string.h>

#include<sys/types.h>

#include<sys/stat.h>

#include<fcntl.h>

#include<unistd.h>

int main()

{

‍ char temp[]="hello,abc!";

int fd;

char pathname[255];

if((fd=open("fileopen.txt",O_WRONLY|O_CREAT,0640))==-1)

{

printf("creat file wrong!");

}

int len=strlen(temp)+1;

write(fd,temp,len);//若fd為0,或這裡直接寫0,則會輸出到屏幕上而不寫入文件中

close(fd);

}

//fileopen2.c


#include<sys/types.h>

#include<sys/stat.h>

#include<unistd.h>

#include<fcntl.h>

#include <stdio.h>

int main()

{

int fa;

int s=12;

int len;

char text[20]="hello,fileopen2!!!";

fa=open("fileopen2.txt",O_WRONLY|O_CREAT,0640);

//len = sprintf(text, "%d", s);

write(fa,text,sizeof(text));

close(fa);

}

//test_system_fprintf_fopen.c


#include<stdio.h>

#include<stdlib.h>

int main()

{

FILE *stream;

char temp[255];

char *a="hello,c!";

stream=fopen("fprintf.txt","w");

fprintf(stream,"%s\n",a);

fprintf(stream,"sb,c++\n");

sprintf(temp,"nl fprintf.txt");

fclose(stream);

printf("%s\n",temp);

system(temp);//system函數參數可以為字符串指針或直接字符串

system("nl fprintf.txt");

exit(0);

return 0;

}

//file-rw.c


#include<stdio.h>

#include<fcntl.h>

#include<unistd.h>

int main()

{

int fdr,fdw;

char temp[255];

char filepath[255];

char fileto[255];

printf("please input the filepath:");

scanf("%s",filepath);

if((fdr=open(filepath,O_RDONLY))==-1)

{

printf("file not found,open failed!");

return -1;

}

else

{

int r_size=read(fdr,temp,255);

close(fdr);

sprintf(fileto,"file-rw.txt");

if((fdw=open(fileto,O_WRONLY|O_CREAT,0640))==-1)

{

printf("open failed!");

return -1;

}

else

{

int w_size=write(fdw,temp,r_size);//相當於復制了所輸入文件.txt中的255個大小的字符串到新文件file-rw.txt中

close(fdw);

printf("have successfully copied 255 chars from \"%s\" to \"%s\"\n",filepath,fileto);

}

}

return 0;

}

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