//PROGRAM TO MERGE 2 FILES//

//PROGRAM TO MERGE 2 FILES//

#include<stdio.h>

#include<fcntl.h>//for open() write() read() close() system call...fcntl.h header file is used..//

#include<unistd.h>

int main()

{

        char buff;

        int count=1,fd,wfd;

        fd=open("source1",O_RDONLY);//open system call is used to open 1st file in O_RDONLY MODE

        wfd=open("desti",O_WRONLY|O_CREAT);//open system call is used to open another file in O_WRONLY MODE..//

        while(count)

        {

                count=read(fd,&buff,1);//READ FROM 1ST FILE ONE BY ONE CHARACTER

                write(wfd,&buff,1);//WRITE INTO 2ND FILE ONE BY ONE CHARACTER

        }

        //lseek(fd,22,SEEK_CUR);

        //BCZ OUR AIM IS TO MERGE 2 FILES MEANS WE WILL READ FROM 1ST FILE WRITE INTO ANOTHER FILE ..THEN WE WILL READ FROM 2ND FILE ..& AGAIN WRITE INTO SAME ANOTHER FILE...//

        fd=open("source2",O_RDONLY);//open another file to read//

        count=1;

        while(count)

        {

                count=read(fd,&buff,1);//READ FROM 2ND FILE

                write(wfd,&buff,1);//WRITE INTO SAME ANOTHER FILE <DESTI>

        }

        close(wfd);//CLOSE FILE DESCRIPTORS//

        return 0;

}