OS Write and Read a file C Program

Operating Systems Lab Manual / OS Write and Read a file C Program

Program Name

Write and read a file C Program.

Theory

File sirectory protocols are used to read and write data to a file using file descriptor.

Program Code

#include<stdio.h> 
#include<sys/stat.h> 
#include<fcntl.h> 
#include<unistd.h> 
int main()
{
int fd; char ch='y';
fd=open("f1",O_CREAT|O_WRONLY,0666);
if(fd==-1)
perror("file cannot be opend");

do
{
read(0,&ch,1);
if(ch=='n') 
break; 
write(fd,&ch,1);
}while(ch!='n'); 
close(fd); 
fd=open("f1",O_RDONLY); 
while(read(fd,&ch,1)!=0)
write(1,&ch,1); 
close(fd);
}

Input:
a1
b1
n

Output:
a1
b1

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