Why while loop is used?

This is the code from a book.
Why while loop is used?

Code:

---

    while ((bytesIn = fread (rec, 1, BUF_SIZE, inFile)) > 0) {
        bytesOut = fwrite (rec, 1, bytesIn, outFile);
        if (bytesOut != bytesIn) {
            perror ("Fatal write error.");
            fclose(inFile); fclose(outFile);
            return 4;
        }
    }

---

I think the code will be same as using without while loop.

You think that without a loop it is still going to repeat reading? Why would you think that?


Quzah.

Code:

---

count = fread( buffer, sizeof( char ), 11, stream );
        cout<<buffer;
        if( ferror( stream ) )      {
            perror( "Read error" );
            break;
        }

---

try this. This will print complete stream.

That's C++. This is a C forum.

ok just do
printf("%s",buffer);
instead of cout

Quote:

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Originally Posted by freiza

Code:

---

count = fread( buffer, sizeof( char ), 11, stream );
        cout<<buffer;
        if( ferror( stream ) )      {
            perror( "Read error" );
            break;
        }

---

try this. This will print complete stream.

---

No it won't. It will read 11 bytes. If the stream has 100000, you won't get more than 11.


Quzah.

Code:

---

count = fread( buffer, sizeof( char ), 100000, stream );

        cout<<buffer;
        if( ferror( stream ) )      {
            perror( "Read error" );
            break;
        }

---

I think this will read 100000 bytes from the stream. (then what is the use of while)
I don't want to sound rubbish. I truly want to know thank you

And what happens if instead I have 10x that amount? Then again, it no longer works. Also, you have to have a buffer that is massive, instead of a small one using a loop. That's why you use a loop: to repeat doing something until you don't need to anymore.

I don't know why you feel the need to make this work without a loop.


Quzah.

I got your point thank you.