CS215 - Lec 5 record organization

� List different methods for record organization.

� Continue with the company class;

� Use fixed length of bytes ,

� Use fixed number of fields

� Use length indicator,

� Use delimiter,

� Use index.

Dr. Hussien M. Sharaf2

Dr. Hussien M. Sharaf3

Fixed length of

bytesVariable length

Length indicator

Record delimiter

Record index

Fixed number of

fields

� A fixed length record file is one in which each record contains the same number of bytes.

� The length must be the max expected length.

� Problems:

1. The estimation of max length.

2. The choice of a character to fill the remaining space.

3. Not readable to human eye.

4. Waste of space.

Dr. Hussien M. Sharaf4

Record 3 Record 4Record 1 Record 2

200 bytes 200 bytes200 bytes 200 bytes

� A fixed number of fields where each field can be of variable size.

� The count must be the max expected count.

� Problems:

1. The estimation of max count.

2. Not readable to human eye.

3. Waste of space in case of an empty field.

Dr. Hussien M. Sharaf5

Record 3 Record 4Record 1 Record 2

180 bytes 190 bytes210 bytes 250 bytes

6 fields 6 fields6 fields 6 fields

� To choose a special character that will not appear within a record and then insert that after each record.

Dr. Hussien M. Sharaf6

3. Record Delimiter

� Problems:

1. The choice of a delimiter character that does not get in the way of processing (ex. White space is not a good choice cause the field may contain spaces within it like “address fields” same for @).

Name EmailID Course

Name EmailID Course

Record1

Record2

\n

\n

Dr. Hussien M. Sharaf7

4. Length indicator

And

5. Index

will be continued at next

lecture

1. Start by determining Output.

2. List the inputs.

3. Think about processing.

� Continue using the CompanyInfo class:

[A] Write a method that takes in ostream and writes to it a company record whose fields have Keyword = Value

� Write a driver to use this class based on the template Menu.

Dr. Hussien M. Sharaf9

� Continue using the CompanyInfo class:

[B] Write a method that takes in istream and reads from it a company record whose fields have Keyword = Value

� Write a driver to use this class based on the template Menu.

Dr. Hussien M. Sharaf10

� Next week is the deadline.

� No excuses.

� Don’t wait until last day.

� I can help you to the highest limit within the next 3 days.

Dr. Hussien M. Sharaf11

1. Delete the “bin” and “obj” folders.

2. Compress the solution folder using winrar.

3. Rename the compressed file as follows:

StudentName_ID_LecExcercise.rar

4. Email to: dr.sharaf@from-masr.com with your ID in the subject.

Dr. Hussien M. Sharaf 12