Hey dudes! I am amazed by this code today:

void saveContacts(vector<Contact> &contacts)
{
    ofstream contactFile{CONTACT_FILE, ios::out};
    // contactFile.seekp(0, ios::beg);
    if (!contactFile)
        cout << "File couldn't be opened for writing\n";
    else
    {
        for (size_t i = 0; i < contacts.size();   i)
        {
            contactFile << contacts[i].firstName << DELIM;
            contactFile << contacts[i].lastName << DELIM;
            contactFile << contacts[i].phoneNumber << DELIM;
            contactFile << contacts[i].emailAddress << "\n";
        }
    }
    contactFile.close();
}

I am wondering about the file not being overwrritten even though it is opened in out mode. Why does this happen. I am totally happy with this behaviour because that's what I wanted, but that has come unintentionally. What are the possible reasons that this is happening??

// contactFile.seekp(0, ios::beg);

whether the above file is commented out or not, the result is same. Please give me the reason, because I wanted this behavior but not on the mercy of hidden bugs.