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Nov 2nd, 2009

Problem when generate ID from txt file

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I would like to automatically generated staff number before generated the staff number i would like to check the staff.txt is the staff number exist. If exist then it will get the last's staff number and continue to adding. But the code that i creating it wont work. Please help to me rewrite.

C++ Syntax (Toggle Plain Text)
void staff::setstaffid()
{
	int count = 0;
 
	ifstream instaffile("staff.txt", ios::in);
 
		if(!instaffile)
		{
			ofstream outstaffile("staff.txt", ios::out);
			outstaffile.close();
 
			ifstream instaffile("staff.txt", ios::in);
		}
 
		instaffile.read(reinterpret_cast<char *>(this), sizeof(staff));
 
		if(instaffile.eof())						//if the staff id is 0 then it will start from 20000
		{
			staffid = 1;
			return;
		}
		else
		{
			while(instaffile && !instaffile.eof())
			{
				count++;
				instaffile.read(reinterpret_cast<char *>(this),sizeof(staff));
			}
		}
 
		staffid = 1 + (count);					//increment the staff id
 
		instaffile.close();
		return;
}
void staff::setstaffid()
{
	int count = 0;

	ifstream instaffile("staff.txt", ios::in);

		if(!instaffile)
		{
			ofstream outstaffile("staff.txt", ios::out);
			outstaffile.close();

			ifstream instaffile("staff.txt", ios::in);
		}

		instaffile.read(reinterpret_cast<char *>(this), sizeof(staff));

		if(instaffile.eof())						//if the staff id is 0 then it will start from 20000
		{
			staffid = 1;
			return;
		}
		else
		{
			while(instaffile && !instaffile.eof())
			{
				count++;
				instaffile.read(reinterpret_cast<char *>(this),sizeof(staff));
			}
		}

		staffid = 1 + (count);					//increment the staff id

		instaffile.close();
		return;
}

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just4why

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Nov 3rd, 2009

-7

Re: Problem when generate ID from txt file

line 17 is probably the wrong way to determine if the file is empty or not. What you should do is seek to end of file then get the file position.

C++ Syntax (Toggle Plain Text)
instaffile.seekg(0, ios::end);
size_t sz = instaffile.tellg();
if( sz == 0)
{
    staffid = 1;
    return;
}
instaffile.seekg(0, ios::end);
size_t sz = instaffile.tellg();
if( sz == 0)
{
    staffid = 1;
    return;
}

The loop at lines 24-28 is also wrong

C++ Syntax (Toggle Plain Text)
instaffile.seekp(0, ios::beg); // go to beginning of tile
count = 0;
while( instaffile.read(reinterpret_cast<char *>(this),sizeof(staff))
{
     ++count;
}
instaffile.seekp(0, ios::beg); // go to beginning of tile
count = 0;
while( instaffile.read(reinterpret_cast<char *>(this),sizeof(staff))
{
     ++count;
}

Last edited by Ancient Dragon; Nov 3rd, 2009 at 1:11 am.

Ancient Dragon

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Nov 3rd, 2009

Re: Problem when generate ID from txt file

The code that you give me is not working. It is other method to write the code again without read the file from staff.txt?

just4why

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