There are those occasions when users require to use a binary file to store information. My project required a structure array that contained 10,415 data records that I wanted to store in a file. The binary file IO routine did the trick. Reporpulating the array was accomplished with a simple read. No database access was required once the structure array was populated.
The structure in question is defined as follows:
[codesyntax lang=”cpp”]
struct user_record_area
{
long long id;
string user_login;
string user_pass;
string user_nicename;
string user_email;
string user_url;
string user_registered;
string user_activation_key;
long user_status;
string user_display_name;
};
[/codesyntax]
The array of structure in question had the following description.
[codesyntax lang=”cpp”]
user_record_area ura [10418];
[/codesyntax]
To read the array to a file using a code block like the one below will produce the desired results.
[codesyntax lang=”cpp”]
void extTools::readBin2()
{
ifstream myFile ("recs.bin", ios::in | ios::binary);
// myfile.seekg()
myFile.read ((char*) &ura, sizeof(ura));
if (!myFile)
{
ura[0].id = 22;
}
myFile.close();
}
[/codesyntax]
To write the array to a file using a code block like the one below will produce the desired results.
[codesyntax lang=”cpp”]
void extTools::writeBin2()
{
ofstream file ("recs.bin", ios::out|ios::binary);
if (file.is_open())
{
int size = sizeof(ura);
file.write((char*) &ura, size);
file.close();
}
else cout << "Unable to open file";
}
[/codesyntax]
Once the file is populated to retrieve data records is a snap (without DBMS access);
Mr. Arch Brooks, Software Engineer, Brooks Computing Systems, LLC authored this article.