does fstream read/write move file pointer

Question

This is kind of a simple question that I hope can be answered easily, do the file stream read and write operations move the pointer along? As an example:

cpo         


        

Answer 1

Yes, that is the way it works. Your examples aren't quite the same, though. Your first example reads from 10000, then 10001, then 10002, etc. The second needs a seek outside the loop to set the initial position. To be 100% equivalent, you need to have your second example look like:

cpos=10000;
dataFile.seekg(cpos,ios::beg);
for (i=0;i<20;i++) {
   dataFile.read(carray[i],1);
}