[Dev-C++] Sequence not recorded/read. Why?

Dear sir,

I tried the discussion list with no success. So, excuse me for coming to you. I 
do not know if I have a program error or a compiler error. Anyway, I can see no 
error on my source code so, please, have a look on it. The source code 
presented is the smallest code that I could write in order to show the problem.

The program records 4 times the sequence 9 a b c d, then close the file, open 
again and reads its contents which should be 4 times the sequence 9 a b c d. 
But it does not happen - it seems that the program reads nothing.
Then, the program records 4 times the sequence 1 2 3 4 5, then close the file, 
open again and reads its contents which should be 4 times the sequence 1 2 3 4 
5.  Perfect, the program reads the file contents as expected.

I could realize that, considering the sequence 0 to ff, the program does not 
read the bytes 9 a b c d 20. There is no problem with the other bytes. I do not 
understand why.

It follows bellow the source code to make tests. The part bellow the 
line //////////////////////////// is identical to the part above this line with 
only one difference to define the start number (1 or 9). The line is:
        ch = 9 + (i%5);         // generates 01 byte (9 to d)               
above this line
        ch = 1 + (i%5);         // generates 01 byte (1 to 5)               
bellow this line

Thank you for your help

Source code:

#include <iostream>
    using namespace std;
#include <fstream>
    using namespace std;

main()
{
    unsigned char ch;

    cout << endl;
    // open file for output
    ofstream arquivo("binary", ios::out|ios::binary);
    // copy bytes to output file
    for (int i=0; i<20; i++) {
        ch = 9 + (i%5);         // generates 01 byte (9 to d)
        arquivo << ch;          // writes 01 byte to out file

        cout.width(3);          // shows the recorded byte
        cout << hex << int(ch);
    }
    arquivo.close();            //finished, close the file.

    cout << endl;
    ch=0; ////// Wrong, it shows this number as result of cout bellow. Why?

    // open file for input
    ifstream arquivo0("binary", ios::in|ios::binary);
    // read bytes from output file
    for (int i=0; i<20; i++)
    {
        arquivo0 >> ch;         // reads 01 byte from out file

        cout.width(3);          // shows the read byte
        cout << hex << int(ch); // it seems that it did not read the byte from 
file!!!
    }
    arquivo0.close();           //finished, close the file.
///////////////////////////////////////////////////////////////////////////////
    cout << endl;
    // open file for output
    ofstream arquivo1("binary", ios::out|ios::binary);
    // copy bytes to output file
    for (int i=0; i<20; i++) {
        ch = 1 + (i%5);         // generates 01 byte (1 to 5)
        arquivo1 << ch;         // writes 01 byte to out file

        cout.width(3);          // shows the recorded byte
        cout << hex << int(ch);
    }
    arquivo1.close();           //finished, close the file.

    cout << endl;
    ch=0; ////// As expected, it does not shows this number as result of cout 
bellow

    // open file for input
    ifstream arquivo2("binary", ios::in|ios::binary);
    // read bytes from output file
    for (int i=0; i<20; i++)
    {
        arquivo2 >> ch;         // reads 01 byte from out file

        cout.width(3);          // shows the read byte
        cout << hex << int(ch);
    }
    arquivo2.close();           //finished, close the file.
}


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