Question

I happened to run across a code example for reading text from a file as follows:

int i; 
char *fileName = "text.txt"; 
ifstream fin(fileName); 

while (fin >> i)
{
do something;
}

This code actually opens and reads space-delimited text, but I don’t understand how it works. How does the file get opened without an “open” or “read” command? Is there a way to rewind back to the beginning of the file? I’m trying to create a dynamically allocated array, which I don’t know how to do until after I’ve counted through the file for the number of scores.

Answer 1

How does the file get opened without an “open” or “read” command?

The ifstream constructor will open the file.

Is there a way to rewind back to the beginning of the file?

Use seekg(). If the EOF has been reached then you need to call clear() before calling seekg().

I’m trying to create a dynamically allocated array

If permitted, you could use std::vector to store the text read which would avoid having to read the contents of the file twice.