From a given file (e.g. input.txt) read the alternate nth byte and write it on another file with the help of “lseek”.
lseek (C System Call): lseek is a system call that is used to change the location of the read/write pointer of a file descriptor. The location can be set either in absolute or relative terms.
off_t lseek(int fildes, off_t offset, int whence);
int fildes : The file descriptor of the pointer that is going to be moved
off_t offset : The offset of the pointer (measured in bytes).
int whence : The method in which the offset is to be interpreted
(rela, absolute, etc.). Legal value r this variable are provided at the end.
return value : Returns the offset of the pointer (in bytes) from the
beginning of the file. If the return value is -1,
then there was an error moving the pointer.
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