read binary file

[earlrainer]

Hi ,

i am not very familiar with c++.

please help me how to read a binary file

someone gave me a binary file which i have to read

the record in the binay file has this structure
Name string(13)
age string(2)
salary string(6)

how can i read this in C++

Thanks

 

[woja]

Try this (which is C as well as C++):

#include <stdio.h>
#include <memory.h>
#include <string.h>

static nRec = 0;

void processRec(
   char* aRec
) {
   /* gets the bits of the record and prints them */
   char name[13 + 1] = &quot;&quot;;
   char age[2 + 1] = &quot;&quot;;
   char salary[6 + 1] = &quot;&quot;;
   memmove(name, aRec, 13);
   memmove(age, aRec + 13, 2);
   memmove(salary, aRec + 15, 6);
   ++nRec;
   printf(
         &quot;Record %d: name=\&quot;%s\&quot;; age=\&quot;%s\&quot; salary=\&quot;%s\&quot;\n&quot;
      ,  name, age, salary
   );
   return;
}

int main() {
   /* open a file in binary mode for reading */
   FILE* fIn = fopen(&quot;myfile.dat&quot;, &quot;rb&quot;);
   char rec[21];
   if (fIn == (FILE*) 0) {
      /* file not openend */
      printf(&quot;Cannot find file.\n&quot;);
   } else {
      /*
         reads each record of 21 characters and processes it
         fread() returns a value less than 21 when the last
         record is read
      */
      while (fread(rec, sizeof(char), 21, fIn) == 21) {
         processRec(rec);
      }
      fclose(fIn);
   }
   return 0;
}

Hope this helps.


________________________________________
Roger J Coult; Grimsby, UK
In the game of life the dice have an odd number of sides.

 

[woja]

Whoops! missed something out:
[tt]
printf(
"Record %d: name=\"%s\"; age=\"%s\" salary=\"%s\"\n"
, name, age, salary
);
[/tt]
should be:
[tt]
printf(
"Record %d: name=\"%s\"; age=\"%s\" salary=\"%s\"\n"
, nRec, name, age, salary
);
[/tt]




________________________________________
Roger J Coult; Grimsby, UK
In the game of life the dice have an odd number of sides.