Reading from file using read function

Question

I have to write a program that reads numbers in separate lines each  Is it possible to read only one line of the file and then read an int from the buffer  and so on until the end of file  It is really hard to find good examples of using read and write   My example is kind of working but I d like to read until it detects   n  char and then convert buffer into int     include  lt fcntl h gt    include  lt stdio h gt    include  lt string h gt   include  lt unistd h gt    include  lt iostream gt   int fd 2    void readFile int fd        unsigned char buffer 10       int bytes read      int k 0      do           bytes read   read fd  buffer  10            k                for int i 0  i lt 10  i                  printf   c   buffer i                        while  bytes read    0       int tab 50    int main int argc  char  argv          if argv 1     NULL    argv 2     NULL                  printf  Function requires two arguments  nGood bye    n                return -1            else           if  access argv 1   F OK     0                fd 0    open argv 1   O RDONLY                     else                fd 0    open argv 1   O WRONLY O CREAT O SYNC  0700               const int size   50                  for int i 0  i lt size  i                          char buf 10                          sprintf buf    d n   i 1                       write fd 0   buf  strlen buf                                      close fd 0                fd 0    open argv 1   O RDONLY               if  access argv 2   F OK     0                   fd 1    open argv 2   O WRONLY               else                  fd 1    open argv 2   O WRONLY O CREAT  0700                        if  access argv 2   F OK     0           fd 1    open argv 2   O WRONLY        else          fd 1    open argv 2   O WRONLY O CREAT  0700         readFile fd 0        close fd 0        close fd 1        Revised code   void readFile int fd        char buffer 10       int bytes read      int k   0      do           char t   0          bytes read   read fd   amp t  1            buffer k      t              printf   c   t           if t      n   amp  amp  t      0                 printf   d   atoi buffer                for int i 0  i lt 10  i                     buffer i    0               k   0                      while  bytes read    0

User · Answer

I am reading some data from a file using read  Here I am reading data in a 2d char pointer but the method is the same for the 1d also  Just read character by character and do not worry about the exceptions because the condition in the while loop is handling the exceptions  D   while    n   read fd  buffer 1    gt  0         if buffer 0       n       r      char  tempData  char   malloc sizeof char   r      for int a 0 a lt r a            tempData a   char  malloc sizeof char  BUF SIZE       memset tempData a  0 BUF SIZE          for int a 0 a lt r-1 a            strcpy tempData a  data a            data tempData      c 0     else     data r-1  c  buffer 0     c      buffer 1    0

User · Answer

Read Byte by Byte and check that each byte against   n  if it is not   then store it into buffer if it is   n  add   0  to buffer and then use atoi      You can read a single byte like this    char c  read fd  amp c 1     See read

User · Answer

fgets would work for you  here is very good documentation on this  - http   www cplusplus com reference cstdio fgets   If you don t want to use fgets  following method will work for you  -  int readline FILE  f  char  buffer  size t len       char c      int i      memset buffer  0  len       for  i   0  i  lt  len  i                  int c   fgetc f           if   feof f                        if  c      r               buffer i    0           else if  c      n                             buffer i    0               return i 1                         else             buffer i    c                    else                       fprintf stderr   read line    recv returned  d n   c            return -1                          return -1

[c] Reading from file using read() function

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